Gerador inteiro de 64 bits com ordenação K Postgresql exclusivo

Função Postgresql – http://www.wekeroad.com/2014/05/29/a-better-id-generator-for-postgresql/ .

Deu a esta função um giro adicional removendo a criação de esquema separada, para que pudesse ser usada no esquema público:

CREATE SEQUENCE global_id_sequence;

CREATE OR REPLACE FUNCTION id_generator
(OUT result bigint) AS $$
DECLARE

our_epoch bigint
:= 1314220021721;
seq_id bigint
;
now_millis bigint
;
-- the id of this DB shard, must be set for each
-- schema shard you have - you could pass this as a parameter too
shard_id
int := 1;
BEGIN
SELECT nextval
('global_id_sequence') % 1024 INTO seq_id;

SELECT FLOOR
(EXTRACT(EPOCH FROM clock_timestamp()) * 1000) INTO now_millis;
result
:= (now_millis - our_epoch) << 23;
result
:= result | (shard_id << 10);
result
:= result | (seq_id);
END;
$$ LANGUAGE PLPGSQL
;

Uso:

CREATE TABLE test_table
(
id bigint NOT NULL DEFAULT id_generator
(),
name text NOT NULL
,
CONSTRAINT test_table_pkey PRIMARY KEY
(id)
)
WITH
(
OIDS
=FALSE
);