On Fri, Apr 10, 2020 at 3:59 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > > They can't be strict because the initial iteration needs to produce > something from a null state and non-null input. nodeAgg's default > behavior won't work for those because nodeAgg doesn't know how to > copy a value of type "internal". > > regards, tom lane
Ah, I think I get it. A copy must happen because the input is likely in a shorter-lived memory context than the state, but nodeAgg's default behavior of copying a by-value datum won't really copy the object pointed to by the pointer wrapped in the datum of "internal" type, so we defer to the combine function. Am I right? Then it follows kinda naturally that those combine functions have been sloppy on arrival since commit 11c8669c0cc . Cheers, Jesse
