[fishstamp82]

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.