On Thu, Jun 30, 2022 at 12:41 AM Simon Riggs <simon.ri...@enterprisedb.com> wrote: > The reason to mention this now is that it would give more space than > 56bit limit being suggested here.
Isn't 2^56 enough, though? Remembering that cluster time runs out when we've generated 2^64 bytes of WAL, if you want to run out of 56 bit relfile numbers before the end of time you'll need to find a way to allocate them in less than 2^8 bytes of WAL. That's technically possible, since SMgr CREATE records are only 42 bytes long, so you could craft some C code to do nothing but create (and leak) relfilenodes, but real usage is always accompanied by catalogue insertions to connect the new relfilenode to a database object, without which they are utterly useless. So in real life, it takes many hundreds or typically thousands of bytes, much more than 256.
