On Wed, Oct 6, 2021 at 9:25 AM Mark Dilger <mark.dil...@enterprisedb.com> wrote: > Thanks for reviewing! > > I expect to post a new version shortly.
Not sure how much it matters, but I have some thoughts on the return value of pg_amcheck. (I'm mostly going into this now because it seems related to how we discuss these issues generally.) A return value of 0 cannot be said to indicate that the database is not corrupt; strictly speaking the verification process doesn't actually verify anything. The null hypothesis is that the database isn't corrupt. pg_amcheck looks for disconfirmatory evidence (evidence of corruption) on a best-effort basis. This seems fundamental. If this philosophy of science stuff seems too abstract, then I can be more concrete: pg_amcheck doesn't even attempt to verify indexes that aren't B-Tree indexes. Clearly we cannot be sure that the database contains no corruption when there happens to be even one such index. And yet the return value from pg_amcheck is still 0 (barring problems elsewhere). I think that it'll always be possible to make *some* argument like that, even in a world where pg_amcheck + amcheck are very feature complete. As I said, it seems fundamental. -- Peter Geoghegan
