v1-0001-Implement-UUID-v7-as-per-IETF-draft.patch

From 044008eef6b72f72c07f40bedfecba05d9448855 Mon Sep 17 00:00:00 2001
From: Andrey Borodin <xformmm@amazon.com>
Date: Fri, 10 Feb 2023 15:38:40 -0800
Subject: [PATCH v1] Implement UUID v7 as per IETF draft

---
 doc/src/sgml/func.sgml                   | 15 +++++++++-
 src/backend/utils/adt/uuid.c             | 38 ++++++++++++++++++++++++
 src/include/catalog/pg_proc.dat          |  3 ++
 src/test/regress/expected/opr_sanity.out |  1 +
 src/test/regress/expected/uuid.out       | 10 +++++++
 src/test/regress/sql/uuid.sql            |  6 ++++
 6 files changed, 72 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e09e289a43..dd6a7914e4 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -13858,14 +13858,27 @@ CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple
    <primary>gen_random_uuid</primary>
   </indexterm>
 
+  <indexterm>
+   <primary>gen_uuid_v7</primary>
+  </indexterm>
+
+  <para>
+   <productname>PostgreSQL</productname> includes two functions to generate a UUID:
+  </para>
   <para>
-   <productname>PostgreSQL</productname> includes one function to generate a UUID:
 <synopsis>
 <function>gen_random_uuid</function> () <returnvalue>uuid</returnvalue>
 </synopsis>
    This function returns a version 4 (random) UUID.  This is the most commonly
    used type of UUID and is appropriate for most applications.
   </para>
+  <para>
+   <productname>PostgreSQL</productname> includes two functions to generate a UUID:
+<synopsis>
+<function>gen_uuid_v7</function> () <returnvalue>uuid</returnvalue>
+</synopsis>
+   This function returns a version 7 (time-ordered + random) UUID.
+  </para>
 
   <para>
    The <xref linkend="uuid-ossp"/> module provides additional functions that
diff --git a/src/backend/utils/adt/uuid.c b/src/backend/utils/adt/uuid.c
index 76ff6c533f..66eb4a35de 100644
--- a/src/backend/utils/adt/uuid.c
+++ b/src/backend/utils/adt/uuid.c
@@ -13,6 +13,8 @@
 
 #include "postgres.h"
 
+#include <sys/time.h>
+
 #include "common/hashfn.h"
 #include "lib/hyperloglog.h"
 #include "libpq/pqformat.h"
@@ -421,3 +423,39 @@ gen_random_uuid(PG_FUNCTION_ARGS)
 
 	PG_RETURN_UUID_P(uuid);
 }
+
+Datum
+gen_uuid_v7(PG_FUNCTION_ARGS)
+{
+	pg_uuid_t  *uuid = palloc(UUID_LEN);
+	struct timeval tp;
+	uint64_t tms;
+
+	gettimeofday(&tp, NULL);
+
+	tms = ((uint64_t)tp.tv_sec) * 1000;
+	tms += ((uint64_t)tp.tv_usec) / 1000;
+
+	tms = pg_hton64(tms<<16);
+
+	/* Fill in time part */
+	memcpy(&uuid->data[0], &tms, 6);
+
+	/* fill everything after the timestamp with random bytes */
+	if (!pg_strong_random(&uuid->data[6], UUID_LEN - 6))
+		ereport(ERROR,
+				(errcode(ERRCODE_INTERNAL_ERROR),
+				 errmsg("could not generate random values")));
+
+	/*
+	 * Set magic numbers for a "version 7" (pseudorandom) UUID, see
+	 * http://tools.ietf.org/html/rfc ???
+	 * https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format#name-creating-a-uuidv7-value
+	 */
+	/* set version field, top four bits are 0, 1, 1, 1 */
+	uuid->data[6] = (uuid->data[6] & 0x0f) | 0x70;
+	/* set variant field, top two bits are 1, 0 */
+	uuid->data[8] = (uuid->data[8] & 0x3f) | 0x80;
+
+	PG_RETURN_UUID_P(uuid);
+}
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index c0f2a8a77c..d448b0a338 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -9042,6 +9042,9 @@
 { oid => '3432', descr => 'generate random UUID',
   proname => 'gen_random_uuid', proleakproof => 't', provolatile => 'v',
   prorettype => 'uuid', proargtypes => '', prosrc => 'gen_random_uuid' },
+{ oid => '3813', descr => 'generate UUID version 7',
+  proname => 'gen_uuid_v7', proleakproof => 't', provolatile => 'v',
+  prorettype => 'uuid', proargtypes => '', prosrc => 'gen_uuid_v7' },
 
 # pg_lsn
 { oid => '3229', descr => 'I/O',
diff --git a/src/test/regress/expected/opr_sanity.out b/src/test/regress/expected/opr_sanity.out
index 02f5348ab1..543ea38f43 100644
--- a/src/test/regress/expected/opr_sanity.out
+++ b/src/test/regress/expected/opr_sanity.out
@@ -857,6 +857,7 @@ sha384(bytea)
 sha512(bytea)
 gen_random_uuid()
 starts_with(text,text)
+gen_uuid_v7()
 macaddr8_eq(macaddr8,macaddr8)
 macaddr8_lt(macaddr8,macaddr8)
 macaddr8_le(macaddr8,macaddr8)
diff --git a/src/test/regress/expected/uuid.out b/src/test/regress/expected/uuid.out
index 0f47232009..c577732e3e 100644
--- a/src/test/regress/expected/uuid.out
+++ b/src/test/regress/expected/uuid.out
@@ -168,5 +168,15 @@ SELECT count(DISTINCT guid_field) FROM guid1;
      2
 (1 row)
 
+-- generation test for v7
+TRUNCATE guid1;
+INSERT INTO guid1 (guid_field) VALUES (gen_uuid_v7());
+INSERT INTO guid1 (guid_field) VALUES (gen_uuid_v7());
+SELECT count(DISTINCT guid_field) FROM guid1;
+ count 
+-------
+     2
+(1 row)
+
 -- clean up
 DROP TABLE guid1, guid2 CASCADE;
diff --git a/src/test/regress/sql/uuid.sql b/src/test/regress/sql/uuid.sql
index 37d954eda1..c54dbf4eb2 100644
--- a/src/test/regress/sql/uuid.sql
+++ b/src/test/regress/sql/uuid.sql
@@ -85,5 +85,11 @@ INSERT INTO guid1 (guid_field) VALUES (gen_random_uuid());
 INSERT INTO guid1 (guid_field) VALUES (gen_random_uuid());
 SELECT count(DISTINCT guid_field) FROM guid1;
 
+-- generation test for v7
+TRUNCATE guid1;
+INSERT INTO guid1 (guid_field) VALUES (gen_uuid_v7());
+INSERT INTO guid1 (guid_field) VALUES (gen_uuid_v7());
+SELECT count(DISTINCT guid_field) FROM guid1;
+
 -- clean up
 DROP TABLE guid1, guid2 CASCADE;
-- 
2.37.0 (Apple Git-136)