Ühel kenal päeval, K, 2007-10-10 kell 17:17, kirjutas Tom Lane:
> "Marko Kreen" <markokr@gmail.com> writes:
> > Could you describe bit more? The is_visible_txid() works
> > on data returned by txid_current_snapshot()? How can there
> > be any subtrans id's if txid_current_snapshot() wont return
> > them?
>
> Ah, I see: txid_current() never reports a subxact ID so there's no need to
> consider them elsewhere in txids either. OK, but this desperately needs
> to be documented.
>
> BTW, I notice that use of txid_current will force assignment of an XID
> in a transaction that might not otherwise have one. Does this matter,
> or is the expectation that it's only going to be used in transactions
> that are making DB modifications anyway?
yes, the common use in Skytools (and now in Slony) is in
insert/update/delete triggers to add current txid to log records.
> regards, tom lane
>
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