Reference library

Database scaling & optimization

Indexing, connection pooling, read replicas, query tuning, and throughput-aware SQL.

1 match
Database scaling & optimization easy

How to Shard Data by User ID Hash in Python

Deterministically map user IDs to shard indexes using an MD5 hash modulo the shard count in Python.

sharding hashing md5
Python 
import hashlib

def shard_id(user_id: str, num_shards: int = 4) -> int:
    """Deterministically map a user_id to a shard index using MD5."""
    digest = hashlib.md5(user_id.encode("utf-8")).hexdigest()
    return int(digest[:8], 16) % num_shards

if __name__ == "__main__":
    user_ids = ["alice", "bob", "carol", "d…
12 0 Open

Browse by section

Each section groups closely related Python snippets.

Database scaling & optimization — Python code examples

What you will find here

This page collects database scaling & optimization snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.

Samples vs tutorials and challenges

Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.

Related coding tools

Free online Python IDE Write and run Python in your browser — no install. Free Python code formatter Format with autopep8 — side-by-side PEP 8 cleanup. Python code samples Copy-ready snippets to study and run in the IDE.