Re: Online verification of checksums

On Thu, Mar 28, 2019 at 05:08:33PM +0100, Michael Banck wrote:
>Hi,
>
>I have rebased this patch now.
>
>I also fixed the two issues Andres reported, namely a zeroed-out
>pageheader and a random LSN. The first is caught be checking for an all-
>zero-page in the way PageIsVerified() does. The second is caught by
>comparing the upper 32 bits of the LSN as well and demanding that they
>are equal. If the LSN is corrupted, the upper 32 bits should be wildly
>different to the current checkpoint LSN.
>
>Well, at least that is a stab at a fix; there is a window where the
>upper 32 bits could legitimately be different. In order to make that as
>small as possible, I update the checkpoint LSN every once in a while.
>

Doesn't that mean we'll report a false positive?

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
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