Hi, On 2020-12-08 12:41:35 -0500, Tom Lane wrote: > FWIW, I kind of like the idea of getting rid of it completely. > Is there really ever a good reason to set it to something different > than that? If not, well, we have too many GUCs already, and each > of them carries nonzero performance, documentation, and maintenance > overhead.
I like the idea of getting rid of it too, but I think we should consider evaluating the concrete hard-coded value a bit more careful than just going for 0.9 based on some old recommendations in the docs. It not being changeable afterwards... I think it might be a good idea to immediately change the default to 0.9, and concurrently try to evaluate whether it's really the best value (vs 0.95, 1 or ...). FWIW I have seen a few cases in the past where setting the target to something very small helped, but I think that was mostly because we didn't yet tell the kernel to flush dirty data more aggressively. Greetings, Andres Freund
