Re: [HACKERS] Something for the TODO list: deprecating abstime and friends

I wrote:
> Hm.  Currently sizeof(struct ControlFileData) = 296, at least on my
> machine.  Letting it grow past 512 would be problematic.  It's hard
> to see getting to that any time soon, though; we don't add fields
> there often.

I wonder if it'd be worth the trouble to stick something like this into
xlog.c:
/* * For reliability's sake, it's critical that pg_control updates * be atomic writes.  That generally means the active
datacan't * be more than one disk sector, which is 512 bytes on common * hardware.  Be very careful about raising this
limit.*/ StaticAssertStmt(sizeof(ControlFileData) <= 512,                  "pg_control is too large for atomic disk
writes");

        regards, tom lane