Is VACUUM still crash-safe?

Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> When VACUUM for a table starts, the transaction is not
> committed yet of cource. After *commit* VACUUM has handled
> heap/index tuples very carefully to be crash-safe before
> 7.1. Currently another vacuum could be invoked in the
> already committed transaction. There has been no such
> situation before 7.1. Yes,VACUUM isn't crash-safe now.
Vadim, do you agree with this argument?  If so, I think it's
something we need to fix.  I don't see what Hiroshi is worried
about, myself, but if there really is an issue here...
        regards, tom lane