CREATE EXTENSION "uuid-ossp"; SELECT uuid_nil(); uuid_nil -------------------------------------- 00000000-0000-0000-0000-000000000000 (1 row) SELECT uuid_ns_dns(); uuid_ns_dns -------------------------------------- 6ba7b810-9dad-11d1-80b4-00c04fd430c8 (1 row) SELECT uuid_ns_url(); uuid_ns_url -------------------------------------- 6ba7b811-9dad-11d1-80b4-00c04fd430c8 (1 row) SELECT uuid_ns_oid(); uuid_ns_oid -------------------------------------- 6ba7b812-9dad-11d1-80b4-00c04fd430c8 (1 row) SELECT uuid_ns_x500(); uuid_ns_x500 -------------------------------------- 6ba7b814-9dad-11d1-80b4-00c04fd430c8 (1 row) -- some quick and dirty field extraction functions -- this is actually timestamp concatenated with clock sequence, per RFC 4122 CREATE FUNCTION uuid_timestamp_bits(uuid) RETURNS varbit AS $$ SELECT ('x' || substr($1::text, 15, 4) || substr($1::text, 10, 4) || substr($1::text, 1, 8) || substr($1::text, 20, 4))::bit(80) & x'0FFFFFFFFFFFFFFF3FFF' $$ LANGUAGE SQL STRICT IMMUTABLE; CREATE FUNCTION uuid_version_bits(uuid) RETURNS varbit AS $$ SELECT ('x' || substr($1::text, 15, 2))::bit(8) & '11110000' $$ LANGUAGE SQL STRICT IMMUTABLE; CREATE FUNCTION uuid_reserved_bits(uuid) RETURNS varbit AS $$ SELECT ('x' || substr($1::text, 20, 2))::bit(8) & '11000000' $$ LANGUAGE SQL STRICT IMMUTABLE; CREATE FUNCTION uuid_multicast_bit(uuid) RETURNS bool AS $$ SELECT (('x' || substr($1::text, 25, 2))::bit(8) & '00000001') != '00000000' $$ LANGUAGE SQL STRICT IMMUTABLE; CREATE FUNCTION uuid_local_admin_bit(uuid) RETURNS bool AS $$ SELECT (('x' || substr($1::text, 25, 2))::bit(8) & '00000010') != '00000000' $$ LANGUAGE SQL STRICT IMMUTABLE; CREATE FUNCTION uuid_node(uuid) RETURNS text AS $$ SELECT substr($1::text, 25) $$ LANGUAGE SQL STRICT IMMUTABLE; -- Ideally, the multicast bit would never be set in V1 output, but the -- UUID library may fall back to MC if it can't get the system MAC address. -- Also, the local-admin bit might be set (if so, we're probably inside a VM). -- So we can't test either bit here. SELECT uuid_version_bits(uuid_generate_v1()), uuid_reserved_bits(uuid_generate_v1()); uuid_version_bits | uuid_reserved_bits -------------------+-------------------- 00010000 | 10000000 (1 row) -- Although RFC 4122 only requires the multicast bit to be set in V1MC style -- UUIDs, our implementation always sets the local-admin bit as well. SELECT uuid_version_bits(uuid_generate_v1mc()), uuid_reserved_bits(uuid_generate_v1mc()), uuid_multicast_bit(uuid_generate_v1mc()), uuid_local_admin_bit(uuid_generate_v1mc()); uuid_version_bits | uuid_reserved_bits | uuid_multicast_bit | uuid_local_admin_bit -------------------+--------------------+--------------------+---------------------- 00010000 | 10000000 | t | t (1 row) -- timestamp+clock sequence should be monotonic increasing in v1 SELECT uuid_timestamp_bits(uuid_generate_v1()) < uuid_timestamp_bits(uuid_generate_v1()); ?column? ---------- t (1 row) SELECT uuid_timestamp_bits(uuid_generate_v1mc()) < uuid_timestamp_bits(uuid_generate_v1mc()); ?column? ---------- t (1 row) -- Ideally, the node value is stable in V1 addresses, but OSSP UUID -- falls back to V1MC behavior if it can't get the system MAC address. SELECT CASE WHEN uuid_multicast_bit(uuid_generate_v1()) AND uuid_local_admin_bit(uuid_generate_v1()) THEN true -- punt, no test ELSE uuid_node(uuid_generate_v1()) = uuid_node(uuid_generate_v1()) END; case ------ t (1 row) -- In any case, V1MC node addresses should be random. SELECT uuid_node(uuid_generate_v1()) <> uuid_node(uuid_generate_v1mc()); ?column? ---------- t (1 row) SELECT uuid_node(uuid_generate_v1mc()) <> uuid_node(uuid_generate_v1mc()); ?column? ---------- t (1 row) SELECT uuid_generate_v3(uuid_ns_dns(), 'www.widgets.com'); uuid_generate_v3 -------------------------------------- 3d813cbb-47fb-32ba-91df-831e1593ac29 (1 row) SELECT uuid_generate_v5(uuid_ns_dns(), 'www.widgets.com'); uuid_generate_v5 -------------------------------------- 21f7f8de-8051-5b89-8680-0195ef798b6a (1 row) SELECT uuid_version_bits(uuid_generate_v4()), uuid_reserved_bits(uuid_generate_v4()); uuid_version_bits | uuid_reserved_bits -------------------+-------------------- 01000000 | 10000000 (1 row) SELECT uuid_generate_v4() <> uuid_generate_v4(); ?column? ---------- t (1 row)