Ask HN: What could a modern database do that PostgreSQL and MySQL can't
One thing PostgreSQL would likely not be able to adapt to, at least without significant effort, is dropping MVCC in favor of more traditional locking protocols.While MVCC is fashionable  nowadays, and more or less every platform offers it at least as an option, my experience, and also opinions I have heard from people using SQL Server and similar platforms professionally, is that for true OLTP at least, good ol’ locking-based protocols in practice outperform MVCC-based protocols (when transactions are well programmed).The “inconvenient truth” [0] that maintaining multiple versions of records badly affects performance might in the future make MVCC less appealing. There’s ongoing research, such as [0], to improve things, but it’s not clear to me at this point that MVCC is a winning idea.[0] https://dl.acm.org/doi/10.1145/3448016.3452783