On Fri, May 27, 2022 at 8:55 AM Andres Freund <and...@anarazel.de> wrote: > > Anyway, how about if we clear this cache for subtrans whenever > > TransactionXmin is advanced and cachedFetchSubXid precedes it? The > > comments atop SubTransGetTopmostTransaction seem to state that we > > don't care about the exact topmost parent when the intermediate one > > precedes TransactionXmin. I think it should preserve the optimization > > because anyway for such cases there is a fast path in > > SubTransGetTopmostTransaction. > > There's not even a proof this does speed up anything useful! There's not a > single benchmark for the patch.
I find it hard to believe that there wasn't even a cursory effort at performance validation before this was committed, but that's what it looks like. -- Peter Geoghegan
