On Tue, Mar 26, 2019 at 12:58 PM Thomas Munro <thomas.mu...@gmail.com> wrote: > ... I think you could probably reclaim that space by > using a more compact representation of vacuumFlags, overflowed, > delayChkpt, nxids (it's funny, the comment says "as tightly as > possible", which clearly isn't the case).
Woops, I take that back. I was thinking of sizeof(bool) == 4, but it's usually 1, so you could probably only squeeze a couple of bytes out by moving those flags. allPgXact elements are currently 12 bytes apart on this system. It's possible that expanding it to 16 bytes would be OK, not sure, and I see there was a whole thread investigating that a couple of years back: https://www.postgresql.org/message-id/flat/CAPpHfdtJY4zOEDsjad6J5AyZMqZcv6gSY9AkKpA7qN3jyQ2%2B1Q%40mail.gmail.com -- Thomas Munro https://enterprisedb.com
