CLOUDFLARE has announced that Hyperdrive for MySQL is now generally available, completing the beta period that introduced MySQL protocol support to their distributed database connection pooler for Cloudflare Workers. The team describes Hyperdrive as a two‑node system (Client and Endpoint) that sits on the same data centre as the Worker and caches, if enabled, queries and results to speed up access to SQL databases.
A key aim during the beta was to meet a production availability target of 99.99%, but investigators found occasional issues in production related to MySQL caching.
The article details a subtle, hard‑to‑reproduce bug that manifested as sporadic empty query responses when caching was enabled and the Client and Endpoint shared a cache in the same data centre. Investigations traced the problem to a mismatch in how result bytes were cached and translated between Hyperdrive’s capabilities and the Worker’s MySQL driver, exacerbated by protocol differences such as CLIENT_DEPRECATE_EOF.
For Client and Endpoint in the same datacentre, this could cause a cached response encoded with Hyperdrive capabilities to be returned without translating to the Worker’s capabilities, producing empty results or hangs. The fix was to always write canonical, translated response bytes into the cache, regardless of which node stored them, after which the empty‑row issue disappeared and reliability rose to 99.99%. The post also reiterates practical steps to deploy Hyperdrive for MySQL, including a sample command using npx wrangler.