--- title: Shopify drops Redis for MySQL at Black Friday scale,... description: Shopify's engineering team replaced Redis with MySQL 8 for inventory reservations and held up through Black Friday 2025 peak traffic at $5.1M/min — the real... canonical: https://daily.dev/posts/shopify-drops-redis-for-mysql-at-black-friday-scale-sqlite-gets-59-faster-via-ai-agent-kykc5q2aa twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Shopify drops Redis for MySQL at Black Friday scale, SQLite gets 59% faster via AI agent | daily.dev og:description: Shopify's engineering team replaced Redis with MySQL 8 for inventory reservations and held up through Black Friday 2025 peak traffic at $5.1M/min — the real... og:url: https://daily.dev/posts/shopify-drops-redis-for-mysql-at-black-friday-scale-sqlite-gets-59-faster-via-ai-agent-kykc5q2aa og:image: https://api.daily.dev/og/posts/Kykc5q2aA.png og:image:alt: Shopify drops Redis for MySQL at Black Friday scale, SQLite gets 59% faster via AI agent og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Shopify drops Redis for MySQL at Black Friday scale, SQLite gets 59% faster via AI agent **[Databases Digest](https://daily.dev/sources/databases_digest)** · 3 min read · 0 upvotes · 0 comments ## Summary Shopify's engineering team replaced Redis with MySQL 8 for inventory reservations and held up through Black Friday 2025 peak traffic at $5.1M/min — the real bottleneck turned out to be connection exhaustion from other checkout processes, not the reservation queries. An AI agent called KISS Sorcar reportedly squeezed a 59% performance improvement out of SQLite in under 8 hours, which is striking given how mature and optimized that codebase already is. CRDTs get a detailed technical treatment, with Automerge's columnar encoding reducing per-keystroke overhead from 300-350 bytes down to roughly 38% above raw text size. Databricks Row Level Security via SQL UDFs is worth knowing about if you're on Unity Catalog, though the Delta time travel incompatibility is a real constraint. ## Content **TLDR:** Shopify's engineering team replaced Redis with MySQL 8 for inventory reservations and held up through Black Friday 2025 peak traffic at $5.1M/min — the real bottleneck turned out to be connection exhaustion from other checkout processes, not the reservation queries. An AI agent called KISS Sorcar reportedly squeezed a 59% performance improvement out of SQLite in under 8 hours, which is striking given how mature and optimized that codebase already is. CRDTs get a detailed technical treatment, with Automerge's columnar encoding reducing per-keystroke overhead from 300-350 bytes down to roughly 38% above raw text size. Databricks Row Level Security via SQL UDFs is worth knowing about if you're on Unity Catalog, though the Delta time travel incompatibility is a real constraint. --- ## Shopify replaced Redis with MySQL 8 for inventory reservations, survived Black Friday 2025 at $5.1M/min The core design uses one row per sellable unit with MySQL's SKIP LOCKED to avoid contention, a bounded pool of 1,000 rows per item/location to keep scans fast, and composite primary keys to reduce lock count. Switching to READ COMMITTED isolation eliminated gap locks; consistent lock ordering and UNION ALL batching handled deadlocks. The actual bottleneck was connection exhaustion from other checkout processes — instrumenting SQL with connection tags at the app layer and aggregating at ProxySQL revealed which callers held connections longest. Cleaning up the checkout path removed 50% of reads and 33% of transactions on the primary; during flash sales, writer CPU stayed under 50% and reader CPU under 16%. [Read more](https://daily.dev/posts/7UecbCOOA) ## AI agent KISS Sorcar achieved 59% performance improvement in SQLite in under 8 hours SQLite is one of the most optimized codebases in existence — getting even 5% faster would be notable. A 59% improvement in under 8 hours from an AI agent is either a very specific workload win or something worth digging into carefully. No details on which query patterns or configurations were targeted, so treat this as a signal to watch rather than a general benchmark result. [Read more](https://daily.dev/posts/krQXuruin) ## Automerge's columnar encoding cut per-keystroke overhead from 300-350 bytes to ~38% above raw text Early Automerge stored 300-350 bytes per keystroke; run-length columnar encoding brought that down to roughly 38% above raw text size. Automerge 3 introduced a native in-memory columnar format and a bloom-filter-based sync protocol. The library now handles tens of millions of operations comfortably, but the post is clear about where CRDTs break down: anything modeling scarcity — bank accounts, ticket reservations — is a poor fit because the local-first, offline-first design can't enforce global constraints. [Read more](https://daily.dev/posts/Devx4b0iQ) --- ## Also notable - **Databricks RLS via SQL UDFs: incompatible with Delta time travel and path-based APIs:** Row Level Security in Databricks uses SQL UDFs with `is_account_group_member()` attached via `ALTER TABLE ... SET ROW FILTER`, but the approach breaks Delta time travel queries, views, Delta Lake path-based APIs, and table clones — worth knowing before you build access control around it. [Read more](https://daily.dev/posts/ccCeLqNdw) - **Redis losing maintainer Madelyn Olson framed as bigger damage than the license change:** After six years of contributions, Madelyn Olson's departure from Redis is being called a more significant loss than the controversial license change that drove the Valkey fork. [Read more](https://daily.dev/posts/MpkL83LFO) ## Similar posts on daily.dev - [We replaced Redis with MySQL for inventory reservations—and it scaled \(2026\)](https://daily.dev/posts/we-replaced-redis-with-mysql-for-inventory-reservations-and-it-scaled-2026--7uecbcooa) · Hacker News · 1 upvotes · 0 comments - [I Tried the “Just Use Postgres” Queue for Six Weeks. SKIP LOCKED Paid Until It Didn’t](https://daily.dev/posts/i-tried-the-just-use-postgres-queue-for-six-weeks-skip-locked-paid-until-it-didn-t-sni9qhs1s) · Medium · 2 upvotes · 0 comments --- Tags: [#redis](https://daily.dev/tags/redis), [#mysql](https://daily.dev/tags/mysql), [#sqlite](https://daily.dev/tags/sqlite), [#crdt](https://daily.dev/tags/crdt) [View this post on daily.dev](https://daily.dev/posts/shopify-drops-redis-for-mysql-at-black-friday-scale-sqlite-gets-59-faster-via-ai-agent-kykc5q2aa) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/shopify-drops-redis-for-mysql-at-black-friday-scale-sqlite-gets-59-faster-via-ai-agent-kykc5q2aa","headline":"Shopify drops Redis for MySQL at Black Friday scale, SQLite gets 59% faster via AI agent","text":"Shopify's engineering team replaced Redis with MySQL 8 for inventory reservations and held up through Black Friday 2025 peak traffic at $5.1M/min — the real bottleneck turned out to be connection exhaustion from other checkout processes, not the reservation queries. 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