On Tue, Feb 8, 2022 at 1:11 PM David Rowley <dgrowle...@gmail.com> wrote:
> Thanks for having a look at this. > > On Fri, 4 Feb 2022 at 13:48, Robert Haas <robertmh...@gmail.com> wrote: > > I think the actual rule is: every path under a Gather or GatherMerge > > must be parallel-safe. > > I've adjusted the patch so that it counts parallel_aware and > parallel_safe Paths independently and verifies everything below a > Gather[Merge] is parallel_safe. > > The diff stat currently looks like: > > src/backend/optimizer/plan/createplan.c | 230 > 1 file changed, 230 insertions(+) > > I still feel this is quite a bit of code for what we're getting here. > I'd be more for it if the path traversal function existed for some > other reason and I was just adding the callback functions and Asserts. > > I'm keen to hear what others think about that. > > David > Hi, + break; + case T_MergeAppend: The case for T_MergeAppend should be left indented. + case T_Result: + if (IsA(path, ProjectionPath)) Since the remaining sub-cases don't have subpath, they are covered by the final `else` block - MinMaxAggPath and GroupResultPath don't need to be checked. For contains_a_parallel_aware_path(), it seems path_type_counter() can return bool indicating whether the walker should return early (when parallel aware count reaches 1). Cheers
