Redis scripts do not expire keys atomically

This post by an Ably engineer discusses the use of Redis for key-based storage in their pub/sub messaging platform and how they resolved a problem related to maintaining the integrity of related keys when using expire operations within Lua scripts. The issue was that naively expiring multiple keys in the same script did not guarantee atomicity, leading to potential inconsistencies. The solution involved using EXPIREAT to set an absolute expiry time for all related keys and reordering key expiry to ensure consistency.