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Allow to_timestamp(float8) to convert float infinity to timestamp infinity.

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With the original SQL-function implementation, such cases failed because
we don't support infinite intervals.  Converting the function to C lets
us bypass the interval representation, which should be a bit faster as
well as more flexible.

Vitaly Burovoy, reviewed by Anastasia Lubennikova
This commit is contained in:
Tom Lane 2016-03-29 17:09:21 -04:00
parent 96f8373cad
commit e511d878f3
7 changed files with 149 additions and 26 deletions
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50
doc/src/sgml/func.sgml
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@ -5579,15 +5579,6 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
argument is the value to be formatted and the second argument is a
template that defines the output or input format.
</para>
<para>
A single-argument <function>to_timestamp</function> function is also
available; it accepts a
<type>double precision</type> argument and converts from Unix epoch
(seconds since 1970-01-01 00:00:00+00) to
<type>timestamp with time zone</type>.
(<type>Integer</type> Unix epochs are implicitly cast to
<type>double precision</type>.)
</para>
<table id="functions-formatting-table">
<title>Formatting Functions</title>
@ -5670,16 +5661,17 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
<entry>convert string to time stamp</entry>
<entry><literal>to_timestamp('05&nbsp;Dec&nbsp;2000', 'DD&nbsp;Mon&nbsp;YYYY')</literal></entry>
</row>
<row>
<entry><literal><function>to_timestamp(<type>double precision</type>)</function></literal></entry>
<entry><type>timestamp with time zone</type></entry>
<entry>convert Unix epoch to time stamp</entry>
<entry><literal>to_timestamp(1284352323)</literal></entry>
</row>
</tbody>
</tgroup>
</table>
<note>
<para>
There is also a single-argument <function>to_timestamp</function>
function; see <xref linkend="functions-datetime-table">.
</para>
</note>
<para>
In a <function>to_char</> output template string, there are certain
patterns that are recognized and replaced with appropriately-formatted
@ -7060,8 +7052,8 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
<entry><type>timestamp with time zone</type></entry>
<entry>
Create timestamp with time zone from year, month, day, hour, minute
and seconds fields. When <parameter>timezone</parameter> is not specified,
then current time zone is used.
and seconds fields; if <parameter>timezone</parameter> is not
specified, the current time zone is used
</entry>
<entry><literal>make_timestamptz(2013, 7, 15, 8, 15, 23.5)</literal></entry>
<entry><literal>2013-07-15 08:15:23.5+01</literal></entry>
@ -7127,6 +7119,19 @@ SELECT regexp_matches('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}');
<entry></entry>
<entry></entry>
</row>
<row>
<entry>
<indexterm>
<primary>to_timestamp</primary>
</indexterm>
<literal><function>to_timestamp(<type>double precision</type>)</function></literal>
</entry>
<entry><type>timestamp with time zone</type></entry>
<entry>Convert Unix epoch (seconds since 1970-01-01 00:00:00+00) to
timestamp</entry>
<entry><literal>to_timestamp(1284352323)</literal></entry>
<entry><literal>2010-09-13 04:32:03+00</literal></entry>
</row>
</tbody>
</tgroup>
</table>
@ -7377,16 +7382,13 @@ SELECT EXTRACT(EPOCH FROM INTERVAL '5 days 3 hours');
</screen>
<para>
Here is how you can convert an epoch value back to a time
stamp:
You can convert an epoch value back to a time stamp
with <function>to_timestamp</>:
</para>
<screen>
SELECT TIMESTAMP WITH TIME ZONE 'epoch' + 982384720.12 * INTERVAL '1 second';
SELECT to_timestamp(982384720.12);
<lineannotation>Result: </lineannotation><computeroutput>2001-02-17 04:38:40.12+00</computeroutput>
</screen>
<para>
(The <function>to_timestamp</> function encapsulates the above
conversion.)
</para>
</listitem>
</varlistentry>

58
src/backend/utils/adt/timestamp.c
View File

@ -737,6 +737,64 @@ make_timestamptz_at_timezone(PG_FUNCTION_ARGS)
PG_RETURN_TIMESTAMPTZ(result);
}
/*
* to_timestamp(double precision)
* Convert UNIX epoch to timestamptz.
*/
Datum
float8_timestamptz(PG_FUNCTION_ARGS)
{
float8 seconds = PG_GETARG_FLOAT8(0);
TimestampTz result;
/* Deal with NaN and infinite inputs ... */
if (isnan(seconds))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp cannot be NaN")));
if (isinf(seconds))
{
if (seconds < 0)
TIMESTAMP_NOBEGIN(result);
else
TIMESTAMP_NOEND(result);
}
else
{
/* Out of range? */
if (seconds <
(float8) SECS_PER_DAY * (DATETIME_MIN_JULIAN - UNIX_EPOCH_JDATE))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range: \"%g\"", seconds)));
if (seconds >=
(float8) SECS_PER_DAY * (TIMESTAMP_END_JULIAN - UNIX_EPOCH_JDATE))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range: \"%g\"", seconds)));
/* Convert UNIX epoch to Postgres epoch */
seconds -= ((POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY);
#ifdef HAVE_INT64_TIMESTAMP
result = seconds * USECS_PER_SEC;
#else
result = seconds;
#endif
/* Recheck in case roundoff produces something just out of range */
if (!IS_VALID_TIMESTAMP(result))
ereport(ERROR,
(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
errmsg("timestamp out of range: \"%g\"",
PG_GETARG_FLOAT8(0))));
}
PG_RETURN_TIMESTAMP(result);
}
/* timestamptz_out()
* Convert a timestamp to external form.
*/

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201603291
#define CATALOG_VERSION_NO 201603292
#endif

2
src/include/catalog/pg_proc.h
View File

@ -1202,7 +1202,7 @@ DATA(insert OID = 1154 ( timestamptz_lt PGNSP PGUID 12 1 0 0 0 f f f t t f i
DATA(insert OID = 1155 ( timestamptz_le PGNSP PGUID 12 1 0 0 0 f f f t t f i s 2 0 16 "1184 1184" _null_ _null_ _null_ _null_ _null_ timestamp_le _null_ _null_ _null_ ));
DATA(insert OID = 1156 ( timestamptz_ge PGNSP PGUID 12 1 0 0 0 f f f t t f i s 2 0 16 "1184 1184" _null_ _null_ _null_ _null_ _null_ timestamp_ge _null_ _null_ _null_ ));
DATA(insert OID = 1157 ( timestamptz_gt PGNSP PGUID 12 1 0 0 0 f f f t t f i s 2 0 16 "1184 1184" _null_ _null_ _null_ _null_ _null_ timestamp_gt _null_ _null_ _null_ ));
DATA(insert OID = 1158 ( to_timestamp PGNSP PGUID 14 1 0 0 0 f f f f t f i s 1 0 1184 "701" _null_ _null_ _null_ _null_ _null_ "select (''epoch''::pg_catalog.timestamptz + $1 * ''1 second''::pg_catalog.interval)" _null_ _null_ _null_ ));
DATA(insert OID = 1158 ( to_timestamp PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 1184 "701" _null_ _null_ _null_ _null_ _null_ float8_timestamptz _null_ _null_ _null_ ));
DESCR("convert UNIX epoch to timestamptz");
DATA(insert OID = 3995 ( timestamp_zone_transform PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 2281 "2281" _null_ _null_ _null_ _null_ _null_ timestamp_zone_transform _null_ _null_ _null_ ));
DESCR("transform a time zone adjustment");

1
src/include/utils/timestamp.h
View File

@ -124,6 +124,7 @@ extern Datum timestamp_cmp_timestamptz(PG_FUNCTION_ARGS);
extern Datum make_timestamp(PG_FUNCTION_ARGS);
extern Datum make_timestamptz(PG_FUNCTION_ARGS);
extern Datum make_timestamptz_at_timezone(PG_FUNCTION_ARGS);
extern Datum float8_timestamptz(PG_FUNCTION_ARGS);
extern Datum timestamptz_eq_timestamp(PG_FUNCTION_ARGS);
extern Datum timestamptz_ne_timestamp(PG_FUNCTION_ARGS);

47
src/test/regress/expected/timestamptz.out
View File

@ -2307,6 +2307,53 @@ SELECT make_timestamptz(2007, 12, 9, 3, 0, 0, 'VET');
Sun Dec 09 07:30:00 2007 UTC
(1 row)
SELECT to_timestamp( 0); -- 1970-01-01 00:00:00+00
to_timestamp
------------------------------
Thu Jan 01 00:00:00 1970 UTC
(1 row)
SELECT to_timestamp( 946684800); -- 2000-01-01 00:00:00+00
to_timestamp
------------------------------
Sat Jan 01 00:00:00 2000 UTC
(1 row)
SELECT to_timestamp(1262349296.7890123); -- 2010-01-01 12:34:56.789012+00
to_timestamp
-------------------------------------
Fri Jan 01 12:34:56.789012 2010 UTC
(1 row)
-- edge cases
SELECT to_timestamp(-1e20::float8); -- error, out of range
ERROR: timestamp out of range: "-1e+20"
SELECT to_timestamp(-210866803200.0625); -- error, out of range
ERROR: timestamp out of range: "-2.10867e+11"
SELECT to_timestamp(-210866803200); -- 4714-11-24 00:00:00+00 BC
to_timestamp
---------------------------------
Mon Nov 24 00:00:00 4714 UTC BC
(1 row)
-- The upper boundary differs between integer and float timestamps, so check the biggest one
SELECT to_timestamp(185331707078400::float8); -- error, out of range
ERROR: timestamp out of range: "1.85332e+14"
-- nonfinite values
SELECT to_timestamp(' Infinity'::float);
to_timestamp
--------------
infinity
(1 row)
SELECT to_timestamp('-Infinity'::float);
to_timestamp
--------------
-infinity
(1 row)
SELECT to_timestamp('NaN'::float);
ERROR: timestamp cannot be NaN
SET TimeZone to 'Europe/Moscow';
SELECT '2011-03-26 21:00:00 UTC'::timestamptz;
timestamptz

15
src/test/regress/sql/timestamptz.sql
View File

@ -403,6 +403,21 @@ SELECT '2007-12-09 04:00:00'::timestamp AT TIME ZONE 'VET';
SELECT make_timestamptz(2007, 12, 9, 2, 0, 0, 'VET');
SELECT make_timestamptz(2007, 12, 9, 3, 0, 0, 'VET');
SELECT to_timestamp( 0); -- 1970-01-01 00:00:00+00
SELECT to_timestamp( 946684800); -- 2000-01-01 00:00:00+00
SELECT to_timestamp(1262349296.7890123); -- 2010-01-01 12:34:56.789012+00
-- edge cases
SELECT to_timestamp(-1e20::float8); -- error, out of range
SELECT to_timestamp(-210866803200.0625); -- error, out of range
SELECT to_timestamp(-210866803200); -- 4714-11-24 00:00:00+00 BC
-- The upper boundary differs between integer and float timestamps, so check the biggest one
SELECT to_timestamp(185331707078400::float8); -- error, out of range
-- nonfinite values
SELECT to_timestamp(' Infinity'::float);
SELECT to_timestamp('-Infinity'::float);
SELECT to_timestamp('NaN'::float);
SET TimeZone to 'Europe/Moscow';
SELECT '2011-03-26 21:00:00 UTC'::timestamptz;