Most read-only user operations are lock-free, however we still take explicit IS/S collection locks for some operations (e.g. in getMatchingPlanCacheEntryStats), and it's possible that some operations that usually are lock-free in some cases take read locks (autoget check, acquisitions check)

We need a better understanding of what operations are taking read-only locks to better asses the user impact when changing locking requirements (e.g. when changing a MODE_S lock to a MODE_X)