Peter Geoghegan <p...@bowt.ie> writes: > On Tue, Aug 4, 2020 at 1:31 PM Tom Lane <t...@sss.pgh.pa.us> wrote: >> while the INSERT_IN_PROGRESS case has none. Simple symmetry >> would suggest that the INSERT_IN_PROGRESS case should be >> >> if (checking_uniqueness || >> HeapTupleIsHeapOnly(heapTuple)) >> // wait
> I had exactly the same intuition. >> but I'm not 100% convinced that that's right. > Why doubt that explanation? First, it's not clear that this is an exact inverse, because HeapTupleIsHotUpdated does more than check the HOT_UPDATED flag. Second, I think there remains some doubt as to whether the DELETE_IN_PROGRESS case is right either. If we were forcing a wait for *every* in-doubt HOT-chain element, not only non-last ones (or non-first ones for the INSERT case, if we use the above fix) then it'd be quite clear that we're safe. But if we want to keep the optimization then I think maybe closer analysis is warranted. regards, tom lane