On Thu, Aug 22, 2024 at 8:07 AM Jelte Fennema-Nio <postg...@jeltef.nl> wrote: > Are the disabled node counts still expected to be stable even with > GEQO? If not, maybe we should have a way to turn them off after all. > Although I agree that always disabling them when COSTS OFF is set is > probably also undesirable. How about a new option, e.g. EXPLAIN > (DISABLED OFF)
Hmm, I hadn't thought about that. There are no GEQO-specific changes in this patch, which AFAIK is OK, because I think GEQO just relies on the core planning machinery to decide everything about the cost of paths, and is really only experimenting with different join orders. So I think if it picks the same join order, it should get the same count of disabled nodes everywhere. If it doesn't pick the same order, you'll get a different plan entirely. I don't think I quite want to jump into inventing a new EXPLAIN option right this minute. I'm not against the idea, but I don't want to jump into engineering solutions before I understand what the problems are, so I think we should give this a little time. I'll be a bit surprised if this doesn't elicit a few strong reactions, but I want to see what people are actually sad (or, potentially, happy) about. -- Robert Haas EDB: http://www.enterprisedb.com
