Re: a few questions (and doubts) about xid

[Luca Ferrari <fluca1978(at)infinito(dot)it>]

Thanks all for your comments. Just another little hint here (sorry for trivial 
questions):

	if (TransactionIdIsCurrentTransactionId(HeapTupleHeaderGetXmax(tuple)))
	{
		if (tuple->t_infomask & HEAP_IS_LOCKED)
			return true;
		if (HeapTupleHeaderGetCmax(tuple) >= GetCurrentCommandId())
			return true;		/* deleted after scan started */
		else
			return false;		/* deleted before scan started */
	}

what does that "deleted after scan started" means? How is possible that the 
current transaction has deleted the tuple with a command higher than the one 
that is still executing? An example could clearify....

Thanks,
Luca