Is psycopg3 a fork of psycopg2, or a replacement upgrade?

Question

I see references to both psycopg2 and psycopg3, but no clear guidance wrt a roadmap for transitioning between the two. I see that over time there is a large body of SO questions regarding psycopg2.

Is psycopg3 intended to be a replacement for psycopg2? Has there been a significant uptake of this version?

Will there be a long-lived version of psycopg2? Are there any compelling reasons to choose one version over the other?

Answer 1

From the documentation of psycopg3:

Psycopg 3 is a newly designed PostgreSQL database adapter for the Python programming language.

Psycopg 3 presents a familiar interface for everyone who has used Psycopg 2 or any other DB-API 2.0 database adapter, but allows to use more modern PostgreSQL and Python features, such as:

• Asynchronous support
• COPY support from Python objects
• A redesigned connection pool
• Support for static typing
• Server-side parameters binding
• Prepared statements
• Statements pipeline
• Binary communication
• Direct access to the libpq functionalities

From a glance, psycopg3 appears to support more modern python and postgresql features like typing and async. Doing so likely required a lot of backwards-incompatible changes from psycopg2, hence the new version and forked development.