On Tue, May 25, 2021 at 2:45 PM Bruce Momjian <bruce@momjian.us> wrote: > Well, if we create a separate nonce counter, we still need to make sure > it doesn't go backwards during a crash, so we have to WAL log it
I think we don't really need a global counter, do we? We could simply increment the nonce every time we write the page. If we want to avoid using the same IV for different pages, then 8 bytes of the nonce could store a value that's different for every page, and the other 8 bytes could store a counter. Presumably we won't manage to write the same page more than 2^64 times, since LSNs are limited to be <2^64, and those are consumed more than 1 byte at a time for every change to any page anywhere.
The nonce does need to be absolutely unique for a given encryption key and therefore needs to be global in some form.
