Re: [HACKERS] Concurrent VACUUM: first results

"Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
>> I wonder whether there isn't a cleaner way to do this.

> I think there exists another reason.
> We couldn't delete index tuples for deleted but not yet committed
> heap tuples.

My first thought was "Good point".  But my second was "why should
vacuum need to deal with that case?".  If vacuum grabs an exclusive
lock on a relation, it should *not* ever see tuples with uncertain
commit status, no?

> If we could start another transaction without releasing exclusive
> lock for the target relation,it would be better.

Seems like that might be doable, if we really do need it.
        regards, tom lane