What is the compatibility of PyPy with a typical web server deployment? I am currently looking at testing compatibility with Tornado -> SQL Alchemy -> psycopg2. It seems like the C-extensions are a common tripping point. I see the recommendation to use psycopg2cffi, but it seems that package's last release was 2019 :(

SQL Alchemy actually points to PyPy in its recommendations of things to try in ORM performance. https://docs.sqlalchemy.org/en/20/faq/performance.html#resul...

For PostgreSQL, psycopg2 is not supported. psycopg2cffi is largely unmaintained, and the 2.9.0 version in PyPI lacks some newer features of psycopg2: the `psycopg2.sql` module and empty result sets raise a RuntimeError in Python 3.7+. The latest commit in on Github does have these changes [1]. Psycopg 3 [2] and pg8000 [3] (as user tlocke mentioned elsewhere) are viable alternates provided you aren't stuck with older versions of PostgreSQL. I have to continue use psycopg2cffi until I can upgrade an old PostgreSQL 9.4 database.

For Microsoft SQL Server, pymssql does not support PyPy [4]. It's under new maintainership so it might gain support in the future. pypyodbc hasn't had any activity since 2022, and no new PyPI release since 2021 [5]. The datatypes returned can differ between libodbc1 versions. On Ubuntu 18.04 in particular: empty string columns are returned as a single space, integer columns are returned as a Decimal. Also, if you encounter a mysterious HY010 error ("Function sequence error"), you may need to upgrade libodbc1 to v2.3.7+ from v2.3.4 using the Microsoft repos.

[1]: https://github.com/chtd/psycopg2cffi [2]: https://pypi.org/project/psycopg/ [3]: https://pypi.org/project/pg8000/ [4]: https://github.com/pymssql/pymssql/pull/517 [5]: https://pypi.org/project/pypyodbc/