Em qui., 11 de set. de 2025 às 12:36, Tom Lane <t...@sss.pgh.pa.us> escreveu:
> Ranier Vilela <ranier...@gmail.com> writes: > > Em qua., 10 de set. de 2025 às 17:35, Tom Lane <t...@sss.pgh.pa.us> > escreveu: > >> This is silently assuming that sizeof(SortItem) is a multiple of > >> alignof(Datum), which on a 32-bit-pointer platform is not true > >> any longer. We ought to MAXALIGN the two occurrences of > >> data->numrows * sizeof(SortItem). > > > We possibly have two more instances? > > > 1. Function ndistinct_for_combination > (src/backend/statistics/mvdistinct.c) > > - items = (SortItem *) palloc(numrows * sizeof(SortItem)); > > + items = (SortItem *) palloc(MAXALIGN(numrows * sizeof(SortItem))); > > > 2. Function build_distinct_groups (src/backend/statistics/mcv.c) > > - SortItem *groups = (SortItem *) palloc(ngroups * sizeof(SortItem)); > > + SortItem *groups = (SortItem *) palloc(MAXALIGN(ngroups * > > sizeof(SortItem))); > > Neither of those have any hazard, because they are not trying to > allocate multiple arrays using address arithmetic. The part of > build_sorted_items that was actually problematic was doing > > ptr += data->numrows * sizeof(SortItem); > > and then assuming that the result was suitably aligned to be > cast to Datum*. > Thanks Tom, for double checking. best regards, Ranier Vilela
