On Fri, 2008-12-19 at 19:29 -0500, Robert Treat wrote: > On Friday 19 December 2008 05:52:42 Simon Riggs wrote: > > BTW, I noticed the other day that Oracle 11g only allows you to have a > > read only slave *or* allows you to continue replaying. You need to > > manually switch back and forth between those modes. They can't do > > *both*, as Postgres will be able to do. That's because their undo > > information is stored off-block in the Undo Tablespace, so is not > > available for standby queries. Nice one, Postgres. > > > > I think this is true for physical replay, but Oracle also offers the option > to > do logical replay (where transaction logs are converted into sql and run > against the standby; i believe this is similar to what continuant is trying > to do with thier latest offering). In that scenario you can do read and > replay at the same time, though I think there are some conflicts possible; > fewer than what postgres will have, since I think most of thier DDL can be > done online.
That is also an option I have argued that we need, BTW. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
