Pub/Sub with PostgreSQL under 40 lines of Python code
How to use PostgreSQL's LISTEN/NOTIFY as a simple message queue with psycopg2 and asyncio - listen.py
Pub/Sub with PostgreSQL under 40 lines of Python code launched on September 4, 2020 with 17 votes, #934 of 3,898 launches that month and more than 75% of that year's launches. The site was still online in September 2026, 6 years on.
In plain words
This is a Python implementation that demonstrates how to build a publish-subscribe messaging system using PostgreSQL in under 40 lines of code. It is for developers who need a lightweight pub/sub solution without external dependencies. The implementation showcases how PostgreSQL's built-in features can handle message queuing and subscription patterns, making it useful for those wanting to understand pub/sub mechanics or integrate simple messaging into Python applications that already use PostgreSQL.
written from the facts on this page · September 2026
From the sources
Anyone knows why conn.set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT) is important here? Not doubting that it is important. Because when I took the line out, the program didn't work. Just asking out of curiosity. psycopg2 is implemented according to PEP-249 (Python Database API Specification v2.0, "dbapi" for short), which states: Note that if the database supports an auto-commit feature, this must be initially off. So at every statement, a transaction is implicitly opened, but not committed, so whenever you want to finish the transaction, you have to explicitly COMMIT , unless you turn on "autocommit" mode ( Django does this by default , deviating from PEP 249 ), which…from gist.github.com
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