Thanks for your continued efforts to get XID64 implemented. > 32kB page may contain then 2^13-2 offsets, each is maxed by 2^18+1.
> Therefore, offset from base will never overflow 2^31 and will always
> fit uint32.
> It appears logical to me. Agree +1 , but I have a question: I remember the XID64 patch got split into a few threads. How are these threads related? The original one was seen as too big a change, so it was broken up after people raised concerns.
Thanks
On Mon, Sep 15, 2025 at 11:42 PM Maxim Orlov <orlovmg@gmail.com> wrote:
Therefore, we can change from each 8 of 32-bit multixact offsets (takes 32-bytes) to one 64-bit offset + 7 of 24-bit offset increments (takes 29-bytes). The actual multixact offsets can be calculated at the fly, overhead shouldn't be significant. What do you think?
Thank you for your review; I'm pleased to hear from you again.
Yes, because the maximum number of mxoff is limited by the number of running transactions, we may do it that way. However, it is a bit wired to have offsets with the 7-byte "base".
I believe we may take advantage of the 64XID patch's notion of putting a
8 byte base followed by 4 byte offsets for particular page.
32kB page may contain then 2^13-2 offsets, each is maxed by 2^18+1.
Therefore, offset from base will never overflow 2^31 and will always
