---
title: "Inside Look at Reddit's Metadata Store"
url: https://daily.dev/posts/inside-look-at-reddit-s-metadata-store-g4g3f9yai
source_url: https://newsletter.systemdesigncodex.com/p/inside-look-at-reddits-metadata-store
type: article
source: "System Design Codex"
published: 2026-03-17T08:52:11.871Z
updated: 2026-03-17T08:52:36.348Z
tags: ["career", "database", "postgresql", "change-data-capture"]
reading_time: 5
upvotes: 14
comments: 0
language: en
---

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# Inside Look at Reddit's Metadata Store

**[System Design Codex](https://daily.dev/sources/systemdesigncodex)** · 5 min read · 14 upvotes · 0 comments

## Summary

Reddit built a unified media metadata store to consolidate scattered metadata from multiple systems into a single AWS Aurora Postgres database. The system handles 100K+ read requests per second with p50 latency of 2.6ms and p99 of 17ms. The migration used dual writes, backfill, and a Kafka-based Change Data Capture pipeline to detect and fix inconsistencies. For future scalability toward an estimated 50TB by 2030, Reddit implemented range-based partitioning using pg_partman and pg_cron, leveraging monotonically increasing post_id values to keep recent partition indexes cached in the buffer pool.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://newsletter.systemdesigncodex.com/p/inside-look-at-reddits-metadata-store>

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---

Tags: [#career](https://daily.dev/tags/career), [#database](https://daily.dev/tags/database), [#postgresql](https://daily.dev/tags/postgresql), [#change-data-capture](https://daily.dev/tags/change-data-capture)

[View this post on daily.dev](https://daily.dev/posts/inside-look-at-reddit-s-metadata-store-g4g3f9yai)