On Sun, Mar 03, 2019 at 07:58:26AM +0100, Fabien COELHO wrote: > I agree that having a server function (extension?) to do a full checksum > verification, possibly bandwidth-controlled, would be a good thing. However > it would have side effects, such as interfering deeply with the server page > cache, which may or may not be desirable.
In what is that different from VACUUM or a sequential scan? It is possible to use buffer ring replacement strategies in such cases using the normal clock-sweep algorithm, so that scanning a range of pages does not really impact Postgres shared buffer cache.
Yeah, I wouldn't worry too much about the effect on the postgres cache when that is done. It could of course have a much worse impact on the os cache or on the "smart" (aka dumb) storage system cache. But that effect will be there just as much with a separate tool.