On Sat, Nov 22, 2025 at 06:28:13AM -0500, Robert Haas wrote: > What would be an issue is if we > regressed some kind of common pattern. I admit that's a bit > speculative and I'm probably being a little paranoid here: doing smart > things is typically better than doing dumb things, and what we're > doing right now is dumb. > > On the other hand, once we ship something, we can't pull it back. If > it causes a problem, someone will call me at 2am and need their system > fixed right now. If my answer is "well, there are no configuration > knobs we can change and no way to get back to the old behavior and I'm > sorry you're having that problem but the only answer is for you to run > all your VACUUMs manually until two years from now when maybe the > algorithm will have been improved," it's not going to be a very good > night. After 15 years at EDB, I've learned that the problem isn't > being wrong per se; it's having no way to get out from under being > wrong.
Yeah. I'm tempted to code up the "weighting factor" GUCs for the next revision. As you've noted, those would be useful for tuning and for reverting back to pre-v19 behavior. Sure, we might end up with a handful of retail GUCs that most users don't need, but that's not so terrible. -- nathan
