Support for FF1-FF6 datetime format patterns

SQL Standard 2016 defines FF1-FF9 format patters for fractions of seconds in
jsonpath .datetime() method and CAST (... FORMAT ...) SQL clause.  Parsing
engine of upcoming .datetime() method will be shared with to_date()/
to_timestamp().

This patch implements FF1-FF6 format patterns for upcoming jsonpath .datetime()
method.  to_date()/to_timestamp() functions will also get support of this
format patterns as positive side effect.  FF7-FF9 are not supported due to
lack of precision in our internal timestamp representation.

Extracted from original patch by Nikita Glukhov, Teodor Sigaev, Oleg Bartunov.
Heavily revised by me.

Discussion: https://postgr.es/m/fcc6fc6a-b497-f39a-923d-aa34d0c588e8%402ndQuadrant.com
Discussion: https://postgr.es/m/CAPpHfdsZgYEra_PeCLGNoXOWYx6iU-S3wF8aX0ObQUcZU%2B4XTw%40mail.gmail.com
Author: Nikita Glukhov, Teodor Sigaev, Oleg Bartunov, Alexander Korotkov
Reviewed-by: Anastasia Lubennikova, Peter Eisentraut

6 files changed, 134 insertions, 0 deletions

diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index b2b45773339..74ecb7c10e6 100644
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -2786,6 +2786,85 @@ SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
  Sun Dec 18 03:18:00 2011 PST
 (1 row)
 
+SELECT i, to_timestamp('2018-11-02 12:34:56', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |         to_timestamp         
+---+------------------------------
+ 1 | Fri Nov 02 12:34:56 2018 PDT
+ 2 | Fri Nov 02 12:34:56 2018 PDT
+ 3 | Fri Nov 02 12:34:56 2018 PDT
+ 4 | Fri Nov 02 12:34:56 2018 PDT
+ 5 | Fri Nov 02 12:34:56 2018 PDT
+ 6 | Fri Nov 02 12:34:56 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.1', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |          to_timestamp          
+---+--------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.1 2018 PDT
+ 3 | Fri Nov 02 12:34:56.1 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1 2018 PDT
+ 5 | Fri Nov 02 12:34:56.1 2018 PDT
+ 6 | Fri Nov 02 12:34:56.1 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.12', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |          to_timestamp           
+---+---------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.12 2018 PDT
+ 4 | Fri Nov 02 12:34:56.12 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12 2018 PDT
+ 6 | Fri Nov 02 12:34:56.12 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |           to_timestamp           
+---+----------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.123 2018 PDT
+ 5 | Fri Nov 02 12:34:56.123 2018 PDT
+ 6 | Fri Nov 02 12:34:56.123 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.1234', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |           to_timestamp            
+---+-----------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1234 2018 PDT
+ 5 | Fri Nov 02 12:34:56.1234 2018 PDT
+ 6 | Fri Nov 02 12:34:56.1234 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.12345', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |            to_timestamp            
+---+------------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1235 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12345 2018 PDT
+ 6 | Fri Nov 02 12:34:56.12345 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ i |            to_timestamp             
+---+-------------------------------------
+ 1 | Fri Nov 02 12:34:56.1 2018 PDT
+ 2 | Fri Nov 02 12:34:56.12 2018 PDT
+ 3 | Fri Nov 02 12:34:56.123 2018 PDT
+ 4 | Fri Nov 02 12:34:56.1235 2018 PDT
+ 5 | Fri Nov 02 12:34:56.12346 2018 PDT
+ 6 | Fri Nov 02 12:34:56.123456 2018 PDT
+(6 rows)
+
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456789', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+ERROR:  date/time field value out of range: "2018-11-02 12:34:56.123456789"
 --
 -- Check handling of multiple spaces in format and/or input
 --
diff --git a/src/test/regress/expected/timestamp.out b/src/test/regress/expected/timestamp.out
index 715680e3302..f772b07d5a4 100644
--- a/src/test/regress/expected/timestamp.out
+++ b/src/test/regress/expected/timestamp.out
@@ -1584,6 +1584,21 @@ SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
             | 2001 1 1 1 1 1 1
 (65 rows)
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamp),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+ to_char_12 |                              to_char                               
+------------+--------------------------------------------------------------------
+            | 0 00 000 0000 00000 000000  0 00 000 0000 00000 000000  000 000000
+            | 7 78 780 7800 78000 780000  7 78 780 7800 78000 780000  780 780000
+            | 7 78 789 7890 78901 789010  7 78 789 7890 78901 789010  789 789010
+            | 7 78 789 7890 78901 789012  7 78 789 7890 78901 789012  789 789012
+(4 rows)
+
 -- timestamp numeric fields constructor
 SELECT make_timestamp(2014,12,28,6,30,45.887);
         make_timestamp        
diff --git a/src/test/regress/expected/timestamptz.out b/src/test/regress/expected/timestamptz.out
index 5551fa6610e..2d6a71ca64b 100644
--- a/src/test/regress/expected/timestamptz.out
+++ b/src/test/regress/expected/timestamptz.out
@@ -1704,6 +1704,21 @@ SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
             | 2001 1 1 1 1 1 1
 (66 rows)
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamptz),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+ to_char_12 |                              to_char                               
+------------+--------------------------------------------------------------------
+            | 0 00 000 0000 00000 000000  0 00 000 0000 00000 000000  000 000000
+            | 7 78 780 7800 78000 780000  7 78 780 7800 78000 780000  780 780000
+            | 7 78 789 7890 78901 789010  7 78 789 7890 78901 789010  789 789010
+            | 7 78 789 7890 78901 789012  7 78 789 7890 78901 789012  789 789012
+(4 rows)
+
 -- Check OF, TZH, TZM with various zone offsets, particularly fractional hours
 SET timezone = '00:00';
 SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";
diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index e356dd563ee..3c8580397ac 100644
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -402,6 +402,15 @@ SELECT to_timestamp('2011-12-18 11:38 +05:20', 'YYYY-MM-DD HH12:MI TZH:TZM');
 SELECT to_timestamp('2011-12-18 11:38 -05:20', 'YYYY-MM-DD HH12:MI TZH:TZM');
 SELECT to_timestamp('2011-12-18 11:38 20',     'YYYY-MM-DD HH12:MI TZM');
 
+SELECT i, to_timestamp('2018-11-02 12:34:56', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.1', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.12', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.1234', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.12345', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+SELECT i, to_timestamp('2018-11-02 12:34:56.123456789', 'YYYY-MM-DD HH24:MI:SS.FF' || i) FROM generate_series(1, 6) i;
+
 --
 -- Check handling of multiple spaces in format and/or input
 --
diff --git a/src/test/regress/sql/timestamp.sql b/src/test/regress/sql/timestamp.sql
index 031b22bc3c1..329987f7eaa 100644
--- a/src/test/regress/sql/timestamp.sql
+++ b/src/test/regress/sql/timestamp.sql
@@ -224,5 +224,13 @@ SELECT '' AS to_char_10, to_char(d1, 'IYYY IYY IY I IW IDDD ID')
 SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
    FROM TIMESTAMP_TBL;
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamp),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+
 -- timestamp numeric fields constructor
 SELECT make_timestamp(2014,12,28,6,30,45.887);
diff --git a/src/test/regress/sql/timestamptz.sql b/src/test/regress/sql/timestamptz.sql
index 28c76d6b72c..f5fee639a01 100644
--- a/src/test/regress/sql/timestamptz.sql
+++ b/src/test/regress/sql/timestamptz.sql
@@ -248,6 +248,14 @@ SELECT '' AS to_char_10, to_char(d1, 'IYYY IYY IY I IW IDDD ID')
 SELECT '' AS to_char_11, to_char(d1, 'FMIYYY FMIYY FMIY FMI FMIW FMIDDD FMID')
    FROM TIMESTAMPTZ_TBL;
 
+SELECT '' AS to_char_12, to_char(d, 'FF1 FF2 FF3 FF4 FF5 FF6  ff1 ff2 ff3 ff4 ff5 ff6  MS US')
+   FROM (VALUES
+       ('2018-11-02 12:34:56'::timestamptz),
+       ('2018-11-02 12:34:56.78'),
+       ('2018-11-02 12:34:56.78901'),
+       ('2018-11-02 12:34:56.78901234')
+   ) d(d);
+
 -- Check OF, TZH, TZM with various zone offsets, particularly fractional hours
 SET timezone = '00:00';
 SELECT to_char(now(), 'OF') as "OF", to_char(now(), 'TZH:TZM') as "TZH:TZM";