> From: Tender Wang <tndrwang@gmail.com> > Sent: Tuesday, June 4, 2024 7:51 PM > Please add more tests. Especially please add some negative tests; > current patch checks that it is safe to apply materialization. It would > be helpful to add tests checking that materialization is not applied > in both checked cases: > 1. when inner join path is not parallel safe > 2. when matpath is not parallel safe > > > > I added a test case that inner rel is not parallel safe. Actually, > matpath will not create if inner rel is not parallel safe. So I didn't add test case for the second scenario. Is there case in which matpath is not parallel safe and inner rel is parallel safe? If right, I think that it would be suitable to add a negative test in a such case.
I looked through create_xxx_path(), and I found that almost path.parallel_safe is assigned from RelOptiInfo.consider_parallel.
Some pathes take subpath->parallel_safe into account(e.g. Material path). In most cases, Material is parallel_safe if rel is parallel
safe. Now I haven't come up a query plan that material is un parallel-safe but rel is parallel-safe.
Sincerely yours, Yuuki Fujii
-- Yuuki Fujii Information Technology R&D Center Mitsubishi Electric Corporation
