Tested with xxhash 0.8.1 and PostgreSQL 14.1 on Linux and macOS.
Think twice before even considering to use it in any serious environment.
Issues are discouraged, pull requests are greatly appreciated.
Make sure you've got the PostgreSQL source code somewhere.
For Ubuntu/pgdg and PostgreSQL 14: apt install postgresql-server-dev-14
=# CREATE EXTENSION xxhash;
=# SELECT url, xxh32(url), xxh64(url), xxh3_64(url), xxh128(url) FROM (SELECT 'https://example.com' AS url) x;
┌─[ RECORD 1 ]───────────────────────────────┐
│ url │ https://example.com │
│ xxh32 │ ba15a4a8 │
│ xxh64 │ b131752760b48654 │
│ xxh3_64 │ 9398cc7c078760e6 │
│ xxh128 │ 4879d6aa9d88e9c7a169c008892d4829 │
└─────────┴──────────────────────────────────┘
=# SELECT url, xxh32b(url), xxh64b(url), xxh3_64b(url), xxh128b(url) FROM (SELECT 'https://example.com' AS url) x;
┌─[ RECORD 1 ]──────────────────────────────────┐
│ url │ https://example.com │
│ xxh32b │ \xba15a4a8 │
│ xxh64b │ \xb131752760b48654 │
│ xxh3_64b │ \x9398cc7c078760e6 │
│ xxh128b │ \x4879d6aa9d88e9c7a169c008892d4829 │
└──────────┴────────────────────────────────────┘