Postgres Nano ID

A tiny, secure, URL-friendly, unique string ID generator for Postgres with prefix support (e.g. cus_1Hh9jz4D8JZKw5JX).

• Small. Just a simple Postgres function.
• Safe. It uses pgcrypto random generator and can be used in clusters.
• Portable. Nano ID was ported to over 20 programming languages.

Get started

Execute the SQL Code in nanoid.sql in your Postgres database. Doing so will crete the nanoid() function that generates a Nano ID.

Examples

SELECT nanoid();
-- fI9CMk9CpKzn2NLPFWLzk

SELECT nanoid('', 4);
-- BPLy

SELECT nanoid('cus_');
-- cus_cjVgkx0ZcloBkDtLa

SELECT nanoid('cus_', 8);
-- cus_CDsm

SELECT nanoid('cus_', 100);
-- cus_vh6np9wmP1Q1dYSWjUR4DMG8MHCs2bNfGezXz42bOBwIXMbx1pM8htS54Gld0G5GH6ipwixrTOWt8EHNQzDLpmG2N72MQSCx

SELECT nanoid('cus_', 4);
-- Query 1 ERROR at Line 1: : ERROR:  The size including the prefix must be greater than 0!
-- CONTEXT:  PL/pgSQL function nanoid(text,integer,text,double precision) line 23 at RAISE
-- Reason: The size must be greater than the prefix length.

Create a table and auto generate a Nano ID for each row:

CREATE TABLE customers(
  id serial PRIMARY KEY,
  public_id text NOT NULL UNIQUE CHECK (public_id LIKE 'cus_%') DEFAULT nanoid('cus_'),
  name text NOT NULL
);

Usage

nano() takes four arguments:

• prefix: The prefix to use for the ID. Defaults to '' (empty string).
• size: The size of the ID (including the prefix). Defaults to 21.
• alphabet: The alphabet to use to generate the ID. Defaults to 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.
• additionalBytesFactor: A factor determining the randomness quality of the generated ID by adjusting the number of random bytes used. A higher value increases randomness at the cost of performance. Default value is 1.02 which is the most optimal value for the default alphabet.

Calculating the additional bytes factor for a custom alphabet

If you change the alphabet of the nanoid() function, you could optimize the performance by calculating a new additional bytes factor with the following SQL statement:

WITH input as (SELECT '23456789abcdefghijklmnopqrstuvwxyz' as alphabet)
SELECT round(1 + abs((((2 << cast(floor(log(length(alphabet) - 1) / log(2)) as int)) - 1) - length(alphabet)::numeric) / length(alphabet)), 2) as "Optimal additional bytes factor"
FROM input;

Utilizing a custom-calculated additional bytes factor in nanoid() enhances string generation performance. This factor determines how many bytes are generated in a single batch, optimizing computational efficiency. Generating an optimal number of bytes per batch minimizes redundant operations and conserves memory.

Thanks

Thanks to nanoid-postgres which was used as a reference for this project.