> This behavior may well be interpreted as a violation of the SQL standard. no it may not this is fully standard compatible behavior and even expected behavio

> This behavior may well be interpreted as a violation of the SQL standard. no it may not this is fully standard compatible behavior and even expected behavior for _any_ SQL database implementing a read committed transaction insulation level also it's a problem which on a theoretically level is not solvable with how SQL works, hence why on stricter isolation levels like serializable committing the transaction in such a situation will fail (in any SQL database) and needs to be retired. (Through in some unusual setups the db might be able to translate retry the transaction by itself, through at the cost of a ton of drawbacks) Anyway reading the postgres documentation is always a good idea, it's not perfect but pretty good.