Ultra-tuned PL/pgSQL Snowflake ID generator for Supabase Postgres. Provides 41-bit millisecond timestamps, 10-bit node IDs, and a 12-bit cached, cycling sequence entirely within a dedicated schema. No C extensions required.

snowflake_id.sql

-- Create separate schema for Snowflake logic. See: https://supabase.com/docs/guides/database/extensions?queryGroups=database-method&database-method=dashboard#enable-and-disable-extensions#:~:text=To%20avoid%20namespace%20pollution,%20we%20do%20not%20recommend%20creating%20other%20entities%20in%20the%20extensions%20schema.
CREATE SCHEMA IF NOT EXISTS snowflake_ext;

-- High-performance 12-bit sequence
CREATE SEQUENCE IF NOT EXISTS snowflake_ext.sequence_12bit
    AS BIGINT
    START 0
    INCREMENT 1
    MINVALUE 0
    MAXVALUE 4095
    CYCLE
    CACHE 1024;

-- The generator function (this is marked VOLATILE for per-call freshness)
CREATE OR REPLACE FUNCTION snowflake_ext.gen_snowflake_id()
    RETURNS BIGINT
    LANGUAGE plpgsql
    VOLATILE
AS $$
DECLARE
    _epoch    CONSTANT BIGINT := 1600000000000;
    _node     CONSTANT BIGINT := 1;
    _now_ms   BIGINT;
    _seq      BIGINT;
BEGIN
    SELECT
        nextval('snowflake_ext.sequence_12bit'),
        FLOOR(EXTRACT(EPOCH FROM clock_timestamp()) * 1000)::BIGINT
    INTO
        _seq,
        _now_ms;

    RETURN
        ((_now_ms - _epoch) << 22)
        | ((_node      & 1023)  << 12)
        |   (_seq       & 4095);
END;
$$;

-- Use this with `SELECT snowflake_ext.gen_snowflake_id();` or make `snowflake_ext.gen_snowflake_id()` your tables' primary key default value