Florian Pflug <fgp.phlo.org@gmail.com> writes:
> Tom Lane wrote:
>> I think txid_current_snapshot should read ActiveSnapshot. If the user wants
>> to get a beginning-of-xact rather than beginning-of-statement snapshot from
>> it, he should be required to call it in a serializable transaction.
> Hm... does txid require that the snapshot it uses a valid in the sense that
> its xmin follows OldestXmin? If not, we could keep the snapshot around for txid,
> but still update our published xmin - which seems to be the main reason we care
> about getting rid of old snapshots at all.
Why should we complicate the main code like that for txid? I have not
heard any argument why the function should be examining
SerializableSnapshot instead of the current transaction snapshot.
regards, tom lane