Generate a int64/bigint unique id using 41 bits of timestamp and 10 bits of sequence.

object_id_64.sql

# https://instagram-engineering.com/sharding-ids-at-instagram-1cf5a71e5a5c

CREATE SEQUENCE IF NOT EXISTS object_id_seq AS smallint
	MINVALUE 0
	MAXVALUE 1023
	CYCLE;

CREATE OR REPLACE FUNCTION object_id_epoch()
	RETURNS bigint
	LANGUAGE sql
	VOLATILE
	AS $$
SELECT floor(extract(EPOCH FROM clock_timestamp()) * 1000) - 1626644283413
$$;
COMMENT ON FUNCTION object_id_epoch IS
	'Get the current object_id timestamp in milliseconds. '
	'Not the same as the UNIX epoch.';

CREATE OR REPLACE FUNCTION next_object_id()
	RETURNS uint8
	LANGUAGE sql
	VOLATILE
	AS $$
SELECT 0
	| object_id_epoch()::uint8 << 23 /* [23..64) 41 bits */
	| nextval('object_id_seq')::uint2 /* [0..10) 10 bits */
$$;
COMMENT ON FUNCTION next_object_id IS
	'Obtain the next object_id. '
	'Collision only occurs when more than >1024/ms ids are created.';