On Tue, 26 Aug 2025 at 15:17, Damien Clochard <[email protected]> wrote: > > Le 25.08.2025 15:33, Greg Sabino Mullane a écrit : > > Your v3 did not get attached to the previous email. > > My bad, here it is
It seems like we have reached a consensus on adding just the random date and timestamp[tz] functions, so I took a more detailed look with an aim to committing this. I'm attaching v4 with a few minor updates: 1). Updated the paragraph of text below "Table 9.6. Random Functions" to also refer to "Table 9.33. Date/Time Functions", so that it's clear that all the comments that follow apply to the date/time random() functions too -- in particular, the part about setseed(). Having reflected on it, I think that's a slightly better option than putting the new functions in Table 9.6, because that's part of a whole section about mathematical functions and everything there refers to number types, not dates/timestamps, so putting the new functions there feels a little out-of-place. 2). Changed check_range_boundaries() to a macro CHECK_RANGE_BOUNDS(). This feels a little neater, since it's such a trivial check, and the datatype is not always int64. 3). Changed the C function names, adding an underscore for better readability and consistency with other date/timestamp functions. 4). Used the DATE/TIMESTAMP_IS_NOBEGIN/NOEND() macros for neatness. 5). I didn't like this error message: ERROR: lower and upper bound cannot be infinite because it's not grammatically correct, so I changed it to this: ERROR: lower and upper bounds must be finite which is an error already used elsewhere for similar checks. This is not quite the same as the errors thrown by random_numeric() -- perhaps that should be changed to match (making its errors the same as the errors thrown by width_bucket_numeric()). 6). It's not necessary to include utils/builtins.h or utils/datetime.h. I think this is now committable, so if there are no objections, I'll push this shortly. Regards, Dean
From e1f3e211a163247236b115432b8fe1345d39b603 Mon Sep 17 00:00:00 2001 From: Dean Rasheed <[email protected]> Date: Mon, 8 Sep 2025 12:13:21 +0100 Subject: [PATCH v4] Add date and timestamp variants of random(min, max). This adds 3 new variants of the random() function: random(min date, max date) returns date random(min timestamp, max timestamp) returns timestamp random(min timestamptz, max timestamptz) returns timestamptz Each returns a random value x in the range min <= x <= max. Author: Damien Clochard <[email protected]> Reviewed-by: Greg Sabino Mullane <[email protected]> Reviewed-by: Dean Rasheed <[email protected]> Reviewed-by: Vik Fearing <[email protected]> Reviewed-by: Chao Li <[email protected]> Discussion: https://postgr.es/m/[email protected] --- doc/src/sgml/func/func-datetime.sgml | 30 +++++++ doc/src/sgml/func/func-math.sgml | 3 +- src/backend/utils/adt/pseudorandomfuncs.c | 104 ++++++++++++++++++++-- src/include/catalog/pg_proc.dat | 12 +++ src/test/regress/expected/random.out | 87 ++++++++++++++++++ src/test/regress/sql/random.sql | 26 ++++++ 6 files changed, 253 insertions(+), 9 deletions(-) diff --git a/doc/src/sgml/func/func-datetime.sgml b/doc/src/sgml/func/func-datetime.sgml index 482fe45f42e..98dd60aa9a7 100644 --- a/doc/src/sgml/func/func-datetime.sgml +++ b/doc/src/sgml/func/func-datetime.sgml @@ -928,6 +928,36 @@ </para></entry> </row> + <row> + <entry role="func_table_entry"><para role="func_signature"> + <indexterm> + <primary>random</primary> + </indexterm> + <function>random</function> ( <parameter>min</parameter> <type>date</type>, <parameter>max</parameter> <type>date</type> ) + <returnvalue>date</returnvalue> + </para> + <para role="func_signature"> + <function>random</function> ( <parameter>min</parameter> <type>timestamp</type>, <parameter>max</parameter> <type>timestamp</type> ) + <returnvalue>timestamp</returnvalue> + </para> + <para role="func_signature"> + <function>random</function> ( <parameter>min</parameter> <type>timestamptz</type>, <parameter>max</parameter> <type>timestamptz</type> ) + <returnvalue>timestamptz</returnvalue> + </para> + <para> + Returns a random value in the range + <parameter>min</parameter> <= x <= <parameter>max</parameter>. + </para> + <para> + <literal>random('1979-02-08'::date,'2025-07-03'::date)</literal> + <returnvalue>1983-04-21</returnvalue> + </para> + <para> + <literal>random('2000-01-01'::timestamptz, now())</literal> + <returnvalue>2015-09-27 09:11:33.732707+00</returnvalue> + </para></entry> + </row> + <row> <entry role="func_table_entry"><para role="func_signature"> <indexterm> diff --git a/doc/src/sgml/func/func-math.sgml b/doc/src/sgml/func/func-math.sgml index 7528dc4cea4..fd821c0e706 100644 --- a/doc/src/sgml/func/func-math.sgml +++ b/doc/src/sgml/func/func-math.sgml @@ -1151,7 +1151,8 @@ <para> The <function>random()</function> and <function>random_normal()</function> - functions listed in <xref linkend="functions-math-random-table"/> use a + functions listed in <xref linkend="functions-math-random-table"/> and + <xref linkend="functions-datetime-table"/> use a deterministic pseudo-random number generator. It is fast but not suitable for cryptographic applications; see the <xref linkend="pgcrypto"/> module for a more diff --git a/src/backend/utils/adt/pseudorandomfuncs.c b/src/backend/utils/adt/pseudorandomfuncs.c index e7b8045f925..1d2a981491b 100644 --- a/src/backend/utils/adt/pseudorandomfuncs.c +++ b/src/backend/utils/adt/pseudorandomfuncs.c @@ -17,6 +17,7 @@ #include "common/pg_prng.h" #include "miscadmin.h" +#include "utils/date.h" #include "utils/fmgrprotos.h" #include "utils/numeric.h" #include "utils/timestamp.h" @@ -25,6 +26,18 @@ static pg_prng_state prng_state; static bool prng_seed_set = false; +/* + * Macro for checking the range bounds of random(min, max) functions. Throws + * an error if they're the wrong way round. + */ +#define CHECK_RANGE_BOUNDS(rmin, rmax) \ + do { \ + if ((rmin) > (rmax)) \ + ereport(ERROR, \ + errcode(ERRCODE_INVALID_PARAMETER_VALUE), \ + errmsg("lower bound must be less than or equal to upper bound")); \ + } while (0) + /* * initialize_prng() - * @@ -129,10 +142,7 @@ int4random(PG_FUNCTION_ARGS) int32 rmax = PG_GETARG_INT32(1); int32 result; - if (rmin > rmax) - ereport(ERROR, - errcode(ERRCODE_INVALID_PARAMETER_VALUE), - errmsg("lower bound must be less than or equal to upper bound")); + CHECK_RANGE_BOUNDS(rmin, rmax); initialize_prng(); @@ -153,10 +163,7 @@ int8random(PG_FUNCTION_ARGS) int64 rmax = PG_GETARG_INT64(1); int64 result; - if (rmin > rmax) - ereport(ERROR, - errcode(ERRCODE_INVALID_PARAMETER_VALUE), - errmsg("lower bound must be less than or equal to upper bound")); + CHECK_RANGE_BOUNDS(rmin, rmax); initialize_prng(); @@ -177,9 +184,90 @@ numeric_random(PG_FUNCTION_ARGS) Numeric rmax = PG_GETARG_NUMERIC(1); Numeric result; + /* Leave range bound checking to random_numeric() */ + initialize_prng(); result = random_numeric(&prng_state, rmin, rmax); PG_RETURN_NUMERIC(result); } + + +/* + * date_random() - + * + * Returns a random date chosen uniformly in the specified range. + */ +Datum +date_random(PG_FUNCTION_ARGS) +{ + int32 rmin = (int32) PG_GETARG_DATEADT(0); + int32 rmax = (int32) PG_GETARG_DATEADT(1); + DateADT result; + + CHECK_RANGE_BOUNDS(rmin, rmax); + + if (DATE_IS_NOBEGIN(rmin) || DATE_IS_NOEND(rmax)) + ereport(ERROR, + errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("lower and upper bounds must be finite")); + + initialize_prng(); + + result = (DateADT) pg_prng_int64_range(&prng_state, rmin, rmax); + + PG_RETURN_DATEADT(result); +} + +/* + * timestamp_random() - + * + * Returns a random timestamp chosen uniformly in the specified range. + */ +Datum +timestamp_random(PG_FUNCTION_ARGS) +{ + int64 rmin = (int64) PG_GETARG_TIMESTAMP(0); + int64 rmax = (int64) PG_GETARG_TIMESTAMP(1); + Timestamp result; + + CHECK_RANGE_BOUNDS(rmin, rmax); + + if (TIMESTAMP_IS_NOBEGIN(rmin) || TIMESTAMP_IS_NOEND(rmax)) + ereport(ERROR, + errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("lower and upper bounds must be finite")); + + initialize_prng(); + + result = (Timestamp) pg_prng_int64_range(&prng_state, rmin, rmax); + + PG_RETURN_TIMESTAMP(result); +} + +/* + * timestamptz_random() - + * + * Returns a random timestamptz chosen uniformly in the specified range. + */ +Datum +timestamptz_random(PG_FUNCTION_ARGS) +{ + int64 rmin = (int64) PG_GETARG_TIMESTAMPTZ(0); + int64 rmax = (int64) PG_GETARG_TIMESTAMPTZ(1); + TimestampTz result; + + CHECK_RANGE_BOUNDS(rmin, rmax); + + if (TIMESTAMP_IS_NOBEGIN(rmin) || TIMESTAMP_IS_NOEND(rmax)) + ereport(ERROR, + errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("lower and upper bounds must be finite")); + + initialize_prng(); + + result = (TimestampTz) pg_prng_int64_range(&prng_state, rmin, rmax); + + PG_RETURN_TIMESTAMPTZ(result); +} diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 118d6da1ace..03e82d28c87 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -3503,6 +3503,18 @@ proname => 'random', provolatile => 'v', proparallel => 'r', prorettype => 'numeric', proargtypes => 'numeric numeric', proargnames => '{min,max}', prosrc => 'numeric_random' }, +{ oid => '6431', descr => 'random date in range', + proname => 'random', provolatile => 'v', proparallel => 'r', + prorettype => 'date', proargtypes => 'date date', + proargnames => '{min,max}', prosrc => 'date_random' }, +{ oid => '6432', descr => 'random timestamp in range', + proname => 'random', provolatile => 'v', proparallel => 'r', + prorettype => 'timestamp', proargtypes => 'timestamp timestamp', + proargnames => '{min,max}', prosrc => 'timestamp_random' }, +{ oid => '6433', descr => 'random timestamptz in range', + proname => 'random', provolatile => 'v', proparallel => 'r', + prorettype => 'timestamptz', proargtypes => 'timestamptz timestamptz', + proargnames => '{min,max}', prosrc => 'timestamptz_random' }, { oid => '1599', descr => 'set random seed', proname => 'setseed', provolatile => 'v', proparallel => 'r', prorettype => 'void', proargtypes => 'float8', prosrc => 'setseed' }, diff --git a/src/test/regress/expected/random.out b/src/test/regress/expected/random.out index 43cf88a3634..7f17b2a1b12 100644 --- a/src/test/regress/expected/random.out +++ b/src/test/regress/expected/random.out @@ -536,3 +536,90 @@ SELECT n, random(0, trim_scale(abs(1 - 10.0^(-n)))) FROM generate_series(-20, 20 20 | 0.60795101234744211935 (41 rows) +-- random dates +SELECT random('1979-02-08'::date,'2025-07-03'::date) AS random_date_multiple_years; + random_date_multiple_years +---------------------------- + 04-09-1986 +(1 row) + +SELECT random('4714-11-24 BC'::date,'5874897-12-31 AD'::date) AS random_date_maximum_range; + random_date_maximum_range +--------------------------- + 10-02-2898131 +(1 row) + +SELECT random('1979-02-08'::date,'1979-02-08'::date) AS random_date_empty_range; + random_date_empty_range +------------------------- + 02-08-1979 +(1 row) + +SELECT random('2024-12-31'::date, '2024-01-01'::date); -- fail +ERROR: lower bound must be less than or equal to upper bound +SELECT random('-infinity'::date, '2024-01-01'::date); -- fail +ERROR: lower and upper bounds must be finite +SELECT random('2024-12-31'::date, 'infinity'::date); -- fail +ERROR: lower and upper bounds must be finite +-- random timestamps +SELECT random('1979-02-08'::timestamp,'2025-07-03'::timestamp) AS random_timestamp_multiple_years; + random_timestamp_multiple_years +--------------------------------- + Fri Jan 27 18:52:05.366009 2017 +(1 row) + +SELECT random('4714-11-24 BC'::timestamp,'294276-12-31 23:59:59.999999'::timestamp) AS random_timestamp_maximum_range; + random_timestamp_maximum_range +----------------------------------- + Wed Mar 28 00:45:36.180395 226694 +(1 row) + +SELECT random('2024-07-01 12:00:00.000001'::timestamp, '2024-07-01 12:00:00.999999'::timestamp) AS random_narrow_range; + random_narrow_range +--------------------------------- + Mon Jul 01 12:00:00.999286 2024 +(1 row) + +SELECT random('1979-02-08'::timestamp,'1979-02-08'::timestamp) AS random_timestamp_empty_range; + random_timestamp_empty_range +------------------------------ + Thu Feb 08 00:00:00 1979 +(1 row) + +SELECT random('2024-12-31'::timestamp, '2024-01-01'::timestamp); -- fail +ERROR: lower bound must be less than or equal to upper bound +SELECT random('-infinity'::timestamp, '2024-01-01'::timestamp); -- fail +ERROR: lower and upper bounds must be finite +SELECT random('2024-12-31'::timestamp, 'infinity'::timestamp); -- fail +ERROR: lower and upper bounds must be finite +-- random timestamps with timezone +SELECT random('1979-02-08 +01'::timestamptz,'2025-07-03 +02'::timestamptz) AS random_timestamptz_multiple_years; + random_timestamptz_multiple_years +------------------------------------- + Tue Jun 14 04:41:16.652896 2016 PDT +(1 row) + +SELECT random('4714-11-24 BC +00'::timestamptz,'294276-12-31 23:59:59.999999 +00'::timestamptz) AS random_timestamptz_maximum_range; + random_timestamptz_maximum_range +-------------------------------------- + Wed Mar 26 14:07:16.980265 31603 PDT +(1 row) + +SELECT random('2024-07-01 12:00:00.000001 +04'::timestamptz, '2024-07-01 12:00:00.999999 +04'::timestamptz) AS random_timestamptz_narrow_range; + random_timestamptz_narrow_range +------------------------------------- + Mon Jul 01 01:00:00.835808 2024 PDT +(1 row) + +SELECT random('1979-02-08 +05'::timestamptz,'1979-02-08 +05'::timestamptz) AS random_timestamptz_empty_range; + random_timestamptz_empty_range +-------------------------------- + Wed Feb 07 11:00:00 1979 PST +(1 row) + +SELECT random('2024-01-01 +06'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail +ERROR: lower bound must be less than or equal to upper bound +SELECT random('-infinity'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail +ERROR: lower and upper bounds must be finite +SELECT random('2024-01-01 +06'::timestamptz, 'infinity'::timestamptz); -- fail +ERROR: lower and upper bounds must be finite diff --git a/src/test/regress/sql/random.sql b/src/test/regress/sql/random.sql index ebfa7539ede..890f14687ef 100644 --- a/src/test/regress/sql/random.sql +++ b/src/test/regress/sql/random.sql @@ -277,3 +277,29 @@ SELECT random(-1e30, 1e30) FROM generate_series(1, 10); SELECT random(-0.4, 0.4) FROM generate_series(1, 10); SELECT random(0, 1 - 1e-30) FROM generate_series(1, 10); SELECT n, random(0, trim_scale(abs(1 - 10.0^(-n)))) FROM generate_series(-20, 20) n; + +-- random dates +SELECT random('1979-02-08'::date,'2025-07-03'::date) AS random_date_multiple_years; +SELECT random('4714-11-24 BC'::date,'5874897-12-31 AD'::date) AS random_date_maximum_range; +SELECT random('1979-02-08'::date,'1979-02-08'::date) AS random_date_empty_range; +SELECT random('2024-12-31'::date, '2024-01-01'::date); -- fail +SELECT random('-infinity'::date, '2024-01-01'::date); -- fail +SELECT random('2024-12-31'::date, 'infinity'::date); -- fail + +-- random timestamps +SELECT random('1979-02-08'::timestamp,'2025-07-03'::timestamp) AS random_timestamp_multiple_years; +SELECT random('4714-11-24 BC'::timestamp,'294276-12-31 23:59:59.999999'::timestamp) AS random_timestamp_maximum_range; +SELECT random('2024-07-01 12:00:00.000001'::timestamp, '2024-07-01 12:00:00.999999'::timestamp) AS random_narrow_range; +SELECT random('1979-02-08'::timestamp,'1979-02-08'::timestamp) AS random_timestamp_empty_range; +SELECT random('2024-12-31'::timestamp, '2024-01-01'::timestamp); -- fail +SELECT random('-infinity'::timestamp, '2024-01-01'::timestamp); -- fail +SELECT random('2024-12-31'::timestamp, 'infinity'::timestamp); -- fail + +-- random timestamps with timezone +SELECT random('1979-02-08 +01'::timestamptz,'2025-07-03 +02'::timestamptz) AS random_timestamptz_multiple_years; +SELECT random('4714-11-24 BC +00'::timestamptz,'294276-12-31 23:59:59.999999 +00'::timestamptz) AS random_timestamptz_maximum_range; +SELECT random('2024-07-01 12:00:00.000001 +04'::timestamptz, '2024-07-01 12:00:00.999999 +04'::timestamptz) AS random_timestamptz_narrow_range; +SELECT random('1979-02-08 +05'::timestamptz,'1979-02-08 +05'::timestamptz) AS random_timestamptz_empty_range; +SELECT random('2024-01-01 +06'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail +SELECT random('-infinity'::timestamptz, '2024-01-01 +07'::timestamptz); -- fail +SELECT random('2024-01-01 +06'::timestamptz, 'infinity'::timestamptz); -- fail -- 2.51.0
