Stefan Kaltenbrunner <stefan@xxxxxxxxxxxxxxxx> wrote: > > Bill Moran wrote: > > Stefan Kaltenbrunner <stefan@xxxxxxxxxxxxxxxx> wrote: > >> Bill Moran wrote: > >>> "hubert depesz lubaczewski" <depesz@xxxxxxxxx> wrote: > >>>> hi, > >>>> i read about some replication system for postgresql, but - as far as i > >>>> know there is none real multi-master replication system for > >>>> postgresql. > >>>> all i have seen are based on "query replication" with various "hacks" > >>>> for specific constructions (like now()). > >>>> my question is - is there any (even fully commercial) multi-master > >>>> replication system for postgresql that will work with all possible > >>>> constructs, triggers, random data and so on? > >>>> i mean - i dont want to bother with choosing to 'note' somehow that > >>>> 'this particular query' has to be replicated somehow. > >>>> i'm thinking about working solution that will allow multi-master connections. > >>>> > >>>> anything? anywhere? > >>> Have you looked at pgpool? > >> afaik pgpool is statement based and not really multimaster either ... > > > > Well, it's multi-master to the degree that all servers are read/write, > > and therefore any server can take over. > > not sure I follow - pgpool will simply replay the queries to each > backend-server that are going through it. I guess I'm comparing it to Slony, which has a clear delineation between master and slave. With pgpool, you don't have the failover procedure in the same way, in that each server can be read/write at all times. > You cannot directly write to the servers (well you can - but that will > likely cause inconsistent data) - and you have all the problems with > non-determinstic queries as well as problems of getting a node back in > sync after a downtime or connection loss. Right. > > How would you define multi-master? > > for true multimaster one would expect to be able to write to all the > nodes and keep the data consistent/sync or have some sort of conflict > resolution for an async solution. Something more like pgcluster II. -- Bill Moran http://www.potentialtech.com
