Cloudflare has officially launched general availability for MySQL support in Hyperdrive, its database connection pooling service for Cloudflare Workers. The service, which previously supported only Postgres, underwent a year-long beta testing phase to ensure reliability.
During the beta, engineers identified and resolved several issues, including encoding errors related to utf8mb4 support and session state resets caused by the COM_RESET_CONNECTION command. These fixes were essential to maintaining consistent database communication.
A critical bug involving empty query results occurred in 0.001% of requests. The issue stemmed from a shared cache conflict between Hyperdrive Client and Endpoint nodes within the same data center, where cached data was stored without accounting for differing client capabilities.
The team discovered that the cache was storing responses encoded for Hyperdrive's capabilities rather than the specific client's requirements. This led to protocol mismatches, causing unexpected empty results or connection hangs for users.
To resolve this, Cloudflare updated the system to store a canonical version of query results in the cache, encoded specifically for Hyperdrive's capabilities. Following this fix, the service achieved a 99.99% success rate for client connections.
