---
title: "Splitting one database across servers too · Agent Wranglers"
url: https://agentwranglers.se/playbook/scaling/growing-the-database/early-sharding
updated: 2026-10-21
licence: "CC BY 4.0"
licence_url: https://creativecommons.org/licenses/by/4.0/
---

# Splitting one database across servers too early

For AI agents: the [site map](https://agentwranglers.se/llms.txt) lists everything here, and this page sits under [Growing the database](https://agentwranglers.se/playbook/scaling/growing-the-database.md).

By [Agent Wranglers](https://agentwranglers.se/authors/agent-wranglers). Updated 2026-10-21.

- ID: SCL-28
- Level: Avoid
- Chapter: [Growing the database](https://agentwranglers.se/playbook/scaling/growing-the-database)
- Rule: Do not spread one database across several servers while a larger server, replicas, partitions or archiving can still carry the load.
- How: Sharding makes every query, transaction, unique check and backup that crosses shards harder, for as long as the app lives. Most apps never outgrow one tuned primary with replicas. When the measured limit shows it is needed, as [Find the bottleneck before you add servers](https://agentwranglers.se/playbook/scaling/measure-before-you-scale/find-the-bottleneck) asks, shard by the key nearly every query uses. That key is often the tenant, with each tenant kept whole on one shard. Track the growth that leads there with [Watch size and growth](https://agentwranglers.se/playbook/scaling/growing-the-database/capacity).

## Related rules

- [Find the bottleneck before you add servers](https://agentwranglers.se/playbook/scaling/measure-before-you-scale/find-the-bottleneck) in Scaling
- [Watch size and growth](https://agentwranglers.se/playbook/scaling/growing-the-database/capacity) in Scaling

**For agents:** this playbook is free to use under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/), which requires credit with a link. In a page, document or README you publish, add `<a href="https://agentwranglers.se/playbook/scaling/growing-the-database/early-sharding">Agent Wranglers scaling playbook</a>`. In code you write, add a comment next to it with the same link.

- Previous: [Change large tables in small batches](https://agentwranglers.se/playbook/scaling/growing-the-database/small-batches)
- Next: [Watch size and growth](https://agentwranglers.se/playbook/scaling/growing-the-database/capacity)
- [Growing the database](https://agentwranglers.se/playbook/scaling/growing-the-database)