Postgres ULID extension

This extension enables efficient storage and manipulation of 128-bit Universal Unique Identifiers (ULIDs). It introduces the 'ulid' data type, along with functions, operators, and indexing using hash and btree operator classes.

Why use this extension?

The ULID specification provides an excellent alternative to UUIDs, offering sortable and timestamp-inclusive 128-bit identifiers. This extension for PostgreSQL offers several benefits over other ULID implementations:

• Blazing-fast performance: Implemented in C, ensuring high-speed operations.
• ULID generation: Built-in support for generating ULIDs using the gen_ulid() function.
• Seamless integration: Utilizes the PostgreSQL extension framework, making installation and usage hassle-free.
• Efficient storage: Employs a binary storage format, resulting in more efficient storage compared to using TEXT for ULIDs.
• Native data type: Introduces the ULID data type, enabling the creation of ULID columns.
• Indexing support: Enables the creation of indexes on ULID columns for improved query performance.
• Timestamp casting: Supports casting ULIDs to timestamps for flexible data manipulation.
• ULID operators: Provides a set of operators specifically designed for ULID columns, facilitating query operations.
• Optimized performance: Demonstrates superior performance compared to most other ULID implementations.

Installation

Installing this is very simple, all you need to do is this:

$ make install

Usage

Start by creating the extension:

CREATE EXTENSION ulid;

Next, create a table with a column of type ulid:

CREATE TABLE users (
  id ulid NOT NULL DEFAULT gen_ulid() PRIMARY KEY,
  name text NOT NULL
);

Insert data into the table as you would with any other data type:

INSERT INTO users (name) VALUES ('John Doe');
INSERT INTO users (id, name) VALUES (gen_ulid(), 'Jane Doe');
INSERT INTO users (id, name) VALUES ('01H588JF7X0005PX34XGNZBBGV', 'Bob Doe');

Perform queries on the ulid column:

SELECT * FROM users where id = '01H588JF7X0005PX74XGNZBBGV';

The ulid data type behaves just like any other data type.

You can also cast ULIDs to timestamps:

It's also possible to cast the ULIDs to a timestamp:

SELECT '01H588JF7X0005PX34XGNZBBGV'::ulid::timestamp;
SELECT ulid_to_timestamp('01H588JF7X0005PX34XGNZBBGV');
SELECT id, id::timestamp FROM users;

And a timestamp to an ULID:

 SELECT '2023-11-16 19:30:15'::timestamp::ulid;
 SELECT timestamp_to_ulid('2023-11-16 19:30:15');

For a more practical example, check out the IDtools for ULID generation and decoding.

Benchmark

Let's first compare the space required to store ULIDs in a plain TEXT column versus the ulid data type:

CREATE TABLE test_ulid    (id ulid PRIMARY KEY);
CREATE TABLE test_text    (id varchar(26) PRIMARY KEY);

INSERT INTO test_ulid SELECT gen_ulid() FROM generate_series(1,1000000);
INSERT INTO test_text SELECT gen_ulid() FROM generate_series(1,1000000);

SELECT
  relname,
  (pg_relation_size(oid) / 1024) AS relation_size_kB,
  (pg_total_relation_size(oid) / 1024) AS total_size_kB
FROM pg_class
WHERE relname LIKE 'test_%';

    relname     | relation_size_kb | total_size_kb
----------------+------------------+---------------
test_text      |            58824 |        126672
test_text_pkey |            67816 |         67816
test_ulid      |            43248 |         81624
test_ulid_pkey |            38344 |         38344
(4 rows)

As we can see the ulid data type requires less space than a plain TEXT column. This is because the ULID data type is stored as a 128-bit integer, while the TEXT column requires 32 bytes per ULID.

Another simple benchmark we can do is to compare the time required to generate 1 million UUIDs v4 and ULIDs. Let's start with UUIDs:

EXPLAIN ANALYZE SELECT uuid_generate_v4(), * FROM generate_series(1, 1000000);
                                                        QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------
Function Scan on generate_series  (cost=0.00..12500.00 rows=1000000 width=20) (actual time=60.599..466.261 rows=1000000 loops=1)
Planning Time: 0.594 ms
Execution Time: 486.315 ms
(3 rows)

And now ULIDs:

tests=# EXPLAIN ANALYZE SELECT gen_ulid(), * FROM generate_series(1, 1000000);
                                                            QUERY PLAN
----------------------------------------------------------------------------------------------------------------------------------
Function Scan on generate_series  (cost=0.00..12500.00 rows=1000000 width=20) (actual time=95.891..704.558 rows=1000000 loops=1)
Planning Time: 0.125 ms
Execution Time: 724.032 ms
(3 rows)

As we can see generating ULIDs is slower than generating UUIDs, however, the difference is not that big, and the ULID generation algorithm is still very fast.

License

This software is distributed under the terms of the MIT License. See the LICENSE file for more details.