On Sat, May 09, 2020 at 06:48:59AM -0300, Ranier Vilela wrote: >Em sáb., 9 de mai. de 2020 às 01:45, Tom Lane <tgl@sss.pgh.pa.us> escreveu: > >> James Coleman <jtc331@gmail.com> writes: >> > There are always full sort groups before any prefix groups can happen, >> > so we know (even though the tooling doesn't) that the 2nd test can >> > never contradict the first. >> >> So maybe an assertion enforcing that would be appropriate? >> Untested, but: >> >> - if (fullsortGroupInfo->groupCount == 0 && >> - prefixsortGroupInfo->groupCount == 0) >> + if (fullsortGroupInfo->groupCount == 0) >> + { >> + Assert(prefixsortGroupInfo->groupCount == >> 0); >> continue; >> + } >> >I agree, asserts always help. >
That doesn't work, because the prefixSortGroupInfo is used before assignment, producing compile-time warnings.
I've pushed a simpler fix without the assert. If we want to make this check, perhaps doing it in incremental sort itself would be better than doing it in explain.
Thanks anyway for the commit. But if you used the first version of my patch, would the author be me and am I as reported?