pgsql数据库手写自动生成雪花id函数教程

Posted 2022-08-09 洛阳泰山

pgsql的雪花id函数实现

先建立雪花id序列

CREATE SEQUENCE "public"."assign_id_seq" 
INCREMENT 1
MINVALUE  1
MAXVALUE 99999999999999999
START 1
CACHE 1
CYCLE ;

ALTER SEQUENCE "public"."assign_id_seq" OWNER TO "postgres";

后建立生成雪花id的函数

CREATE OR REPLACE FUNCTION "public"."snow_next_id"(OUT "result" int8)
  RETURNS "pg_catalog"."int8" AS $BODY$
DECLARE
   our_epoch bigint := 1314220021721;

   seq_id bigint;
   now_millis bigint;
   shard_id int := 5;
BEGIN
   seq_id := nextval('assign_id_seq') % 1024;
   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;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

ALTER FUNCTION "public"."snow_next_id"(OUT "result" int8) OWNER TO "postgres";

函数使用

SELECT snow_next_id();

输出结果

数据库表id主键设置默认值

ok，这样就可以，插入数据时候，自动生成雪花id了！！！