Ühel kenal päeval, K, 2007-10-10 kell 17:17, kirjutas Tom Lane: > "Marko Kreen" <[EMAIL PROTECTED]> 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 > > ---------------------------(end of broadcast)--------------------------- > TIP 7: You can help support the PostgreSQL project by donating at > > http://www.postgresql.org/about/donate ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org