The schroedinger equation could be rewritten as two coupled equations without the need for complex numbers. Complex numbers just simplify things and "beautify it", but there is nothing "fundamental" about it, its just representation.
For example 1) Let's be clear about what we are doing.
If you are running in RC isolation, and perform a select sum() from table, you are reading values committed by other threads BEFORE the select statement began, you are not getting other threads committed values during the select, you are not breaking ACID.
If you are suggesting that running a simple BEGIN; select sum() from table; COMMIT is breaking acid in a default RC level, you are wrong and should best avoid commenting on isolation levels in RDBMS online, to not confuse people further.
If you are however suggesting that we are breaking ACID if we do app side stupidity such as:
value1=BEGIN; SELECT value from table where id=1;commit
value2=......
sum = value1+value2....+value10
Then yes obviously its not acid but nobody in their right minds should be doing that. Even juniors quickly learn that this is incorrect code.
If you are suggesting we do repeatable reads in RC then yes its obviously not ACID but your example does not mention repeatable summations only a single one.
Postgres as an example is ACID compliant if you want it to be. All those databases that have full serialization possible do utilize RC by default which is enough to prevent dirty writes and was my original point.
RE: "All it knows is that you're trying to write a 6. If someone else wrote a 6 or a 7 in the meantime, then your transaction may have 'meant' (+0) or (-1)."
This is not how it works at all. This is called dirty writes and is by default prevented by ACID compliant databases, no matter the isolation level. The second transaction commit will be rejected by the transaction manager.
Even if you start a transaction from your application, it does not change this still.
I had this problem for a long time, the only thing that worked was installing an ad on that removes recommendations. The only thing I use youtube for today is intentionally following ASL (starcraft broodwar) in korea.
The ad-on makes the home screen completely white/empty, meaning I just get reminded constantly ohh, yeah I am not supposed to use youtube unless there is something particular I want to watch.
The tickers for months are not obvious to me, and since its a 6-week moving average and not point in time, the numbers are a bit hard to intuitively grasp.
To me it looks like the drop is harder since averaging smooths out the points, so end of july 2025 the adoption is not exactly 12%, but probably more like 8%, where its closer to end of 2023.
It seems big tech is putting a big break on AI tooling, for now.