psycache 26.2.0

A psycopg-Backed PostgreSQL Cache

psycache: psycopg-Backed PostgreSQL Cache

A simple key-value cache that stores JSON in PostgreSQL through psycopg 3, with TTL-based expiration and pluggable instrumentation.

• Sync and async ✔︎
• Type-safe ✔︎
• Adapters for SQLAlchemy and psycopg-pool ✔︎

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psycache uses an unlogged table for performance and stores values as JSONB for versatility.

It's a great fit when you already have PostgreSQL and need a fast cache without introducing another piece of infrastructure like Redis. For example, you can safely share a SQLAlchemy Engine (or AsyncEngine) with psycache.

Quick Start

Let's hitch-hike on a SQLAlchemy engine as a quick example!

First, install psycache from PyPI with the sqlalchemy extra:

$ uv pip install "psycache[sqlalchemy]"

Initialize the cache table once (python -Im psycache init-db <dsn> does the same from the shell), then store and retrieve JSON with a TTL:

import psycopg

from sqlalchemy import create_engine

import psycache

from psycache import PostgresCache
from psycache.sqlalchemy import SQLAlchemyCachePool

with psycopg.connect(
    "postgresql://psycache@127.0.0.1/psycache", autocommit=True
) as conn:
    psycache.init_db(conn)

engine = create_engine("postgresql+psycopg://psycache@127.0.0.1/psycache")
cache = PostgresCache(SQLAlchemyCachePool(engine))

cache.put_raw("user:alice", {"score": 42}, ttl=300)
value = cache.get_raw("user:alice")
# {"score": 42}

engine.dispose()

Documentation

Full documentation lives at https://psycache.hynek.me/.

Credits

psycache is written by Hynek Schlawack and distributed under the terms of the MIT license.

The development is kindly supported by my employer Variomedia AG and all my fabulous GitHub Sponsors.