(2013/07/20 1:11), Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: >> On 2013-07-20 00:49:11 +0900, Hiroshi Inoue wrote: >>> Using SnapshotSelf instead of SnapshotNow for currtid_ () wouldn't >>> matter. > >> I think it actually might. You could get into dicey situations if you >> use currtid_ in a query performing updates or inserts because it would >> see the to-be-inserted tuple... > > I'm pretty sure Hiroshi-san was only opining about whether it would > matter for ODBC's usage. IIUC, ODBC is using this function to re-fetch > rows that it inserted, updated, or at least selected-for-update in a > previous command of the current transaction, so actually any snapshot > would do fine. > > In any case, since I moved the goalposts by suggesting that SnapshotSelf > is just as dangerous as SnapshotNow, what we need to know is whether > it'd be all right to change this code to use a fresh MVCC snapshot; > and if not, why not. It's pretty hard to see a reason why client-side > code would want to make use of the results of a non-MVCC snapshot.
OK I agree to replace SnapshotNow for currtid_xx() by a MVCC-snapshot. regards, Hiroshi Inoue -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
