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
