Seems we still have not addressed this. ---------------------------------------------------------------------------
On Sat, May 25, 2013 at 10:18:57AM +0100, Simon Riggs wrote: > On 21 May 2013 19:16, Fujii Masao <masao.fu...@gmail.com> wrote: > > > We cannot run parallel pg_dump on the standby server because > > pg_export_snapshot() always fails on the standby. Is this the oversight > > of parallel pg_dump or pg_export_snapshot()? > > > > pg_export_snapshot() fails in the standby because it always assigns > > new XID and which is not allowed in the standby. Do we really need > > to assign new XID even in the standby for the exportable snapshot? > > Having looked at the code, I say No, we don't *need* to. > > There are various parts of the code that deal with > takenDuringRecovery, so much of this was clearly intended to work in > recovery. > > We use the topXid for the name of the snapshot file. That is clearly > unnecessary and we should be using the virtualxid instead like we do > elsewhere. We also use the topXid to test whether it is still running, > though again, we could equally use the virtualxid instead. There is no > problem with virtualxids possibly not being active anymore, since if > we didn't have an xid before and don't have one now, and the xmin is > the same, the snapshot is still valid. > > I think we should treat this as a bug and fix it in 9.3 while we're > still in beta. Why? Because once we begin using the topXid as the > filename we can't then change later to using the vxid. > > -- > Simon Riggs http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers