Hi, Currently a good bit of time evaluation more complex expressions is spent checking whether a strict [transition] function should be called or not. There's a good number of cases where we could optimize that away based on the underlying data - if e.g. a slot column refers to a NOT NULL column (cf [1]), we do not need to do the NOT NULL checks.
A significant limit of that is that for even slightly morecomplex expressions, say a + b + c that doesn't work for all the operator invocations, because even though functions like int8pl are strict, we do *not* guarantee that the return value is also strict. Thus I wonder if we shouldn't introduce a 'really strict' volatility level that signals, in addition to normal strict guarantees, that no other case returns NULL. In a lot of cases that should allow us to completely eliminate strictness checks from execution. I don't plan to work on this anytime soon, but I though it's interesting enough to put out there and see what others think. Greetings, Andres Freund [1] http://archives.postgresql.org/message-id/20171206093717.vqdxe5icqttpxs3p%40alap3.anarazel.de
