Re: Online verification of checksums

On Tue, Mar 19, 2019 at 02:44:52PM -0700, Andres Freund wrote:
> That's *PRECISELY* my point. I think it's a bad idea to do online
> checksumming from outside the backend. It needs to be inside the
> backend, and if there's any verification failures on a block, it needs
> to acquire the IO lock on the page, and reread from disk.

Yeah, FWIW, Julien Rouhaud was mentioning me that we could use
mdread() and loop over the blocks so as we don't finish loading
corrupted blocks into shared buffers, checking on the way if the block
is already in shared buffers or not.
--
Michael