"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?
regards, tom lane