But the MAX_STORAGE_SIZE_MB is not a hard limit
I’ve seen this occur in production systems with heavy ad-hoc workloads. As the Query Store gathers data, there seems to be a point where the writes are queued up. When they are written to disk, the max size can be exceeded.
Anecdotally, I’ve seen a production systems where the max size has been vastly exceeded. But let me show you an example on a small scale on my demo machine.
Click through for a demonstration on the small. I’d much rather go over my self-imposed limit than lose useful data, so I’m okay with that decision. If you’re extremely tight on disk space, however, it’s good to know this detail.