Robert Haas <robertmhaas@gmail.com> writes:
> Now, that having been said, I'm not sure it's a good idea to tinker
> with the behavior for v10. We could change the new-splitpoint code so
> that it loops over all the pages in the new splitpoint and zeroes them
> all, instead of just the last one.
Why would we do that? That would change the behavior from something
that's arguably OK (at least given the right filesystem) to something
that's clearly not very OK.
> It's too late to start making significant or controversial design
> changes at this point, and you could argue that this is a preexisting
> design defect which the WAL-logging patch wasn't necessarily obligated
> to fix.
Yes, and it is certainly that, and no this patch wasn't chartered to fix
it. I don't have a problem with leaving things like this for v10.
FWIW, I'm not certain that Stephen is correct to claim that we have
some concrete problem with sparse files. We certainly don't *depend*
on sparse storage anyplace else, nor write data in a way that would be
likely to trigger it; but I'm not aware that we need to work hard to
avoid it.
regards, tom lane