Greg Stark <gsstark(at)mit(dot)edu> writes:
> I think we need posix_fallocate().
The problem with posix_fallocate (other than questionable portability)
is that it doesn't appear to guarantee anything at all about what is in
the space it allocates. Worst case, we might find valid-looking
Postgres data there (eg, because a block was recycled from some recently
dropped table). If we have to write something anyway to zero the space,
what's the point?
regards, tom lane