HackerAre We There Yet - Rich Hickey
Zhang JianYouTube ↗
Further reading 2
Can today’s record explain yesterday’s decision? →Keep the value a decision actually used so that later changes do not erase its explanation.Can one record tell you both now and then? →Two reads disagree. First ask which moment each value describes, then who can change it. Keeping history and coordinating writes solve different problems.This video helps answer · What does a snapshot promise its reader?
Caption notes
Separate identity from the value it takes at a particular moment. Stable snapshots and explicit coordination let observers read without blocking change.
Original passages · 5
the state is a snapshot this entity has this value at this point in timethe next version of the value shares a lot of structure with the prior versionmulti-version concurrency control is that readers don't impede writerskey characteristic of a value is that it's immutablethis box right perception does not interfere with process