There are some good news for postgresql 9.0: http://www.postgresql.org/docs/9.0/interactive/warm-standby.html
some of those features above are possible on 8.4 with some difficult configuration tricks, see wiki.postgresql.org. mic 2010/11/11 mdipierro <[email protected]>: > Hi Ron, > I do not much about this topic. Will single master be enough? > You may want to look into these tools as well. > > http://www.slony.info/ > http://www.sistemasagiles.com.ar/trac/wiki/PyReplicaEn > https://public.commandprompt.com/projects/replicator > > > > > On Nov 11, 1:51 pm, ron_m <[email protected]> wrote: >> Any of you have experience with Bucardo or pgpool-II as a replication >> add-on? >> >> Some background: >> I switched from MySQL to PostgreSQL very cleanly using web2py as the >> vehicle. Sort description to document the process: Made a copy of the >> app, removed the content of the databases directory, added the >> prerequisite components (database and driver) to the system, created >> an empty DB, changed the connection string in the model, started MySQL >> verison of app in shell mode and ran all the data out to one CSV file >> and finally started the PostgreSQL version up in shell mode and did an >> import of the same CSV file followed by a db.commit(). After all that >> the application worked except for one group by orderby query >> PostgreSQL didn't like which was easy to fix and the change worked in >> MySQL as well. This was a database with 28 tables linked with lots of >> relations. >> >> My compliments to this great application server and infrastructure >> surrounding it. Of the available migration tools I found out on the >> net, most failed to work and would require extensive manual editing. >> >> The application will be installed in 10 locations scattered all over >> Alaska. All the locations are connected by a WAN with IPSEC to form a >> VPN so it looks like it is all in the same room except for network >> performance. >> >> Each location must survive a network outage and continue to work, The >> weather can be a problem up there. >> >> Any data tables that change rapidly are to remain local to each >> location. >> >> About 2/3 of the database is configuration information which changes >> very slowly. One table if this were running would have changed once in >> 5 years. Some tables change more often as employees come and go or >> equipment is added to a location. Config changes can be delayed by >> downed connections so eventual consistency is okay. >> >> I need something automatic since the people using the system are not >> technical and cannot be depended on to to a task. >> >> By restricting the application I could get the updates to one database >> instance but then there is a time delay until the local copy is in >> sync. >> >> I looked at MySQL Replication as described in the Linux Journal >> article July 2010 where they do a ring which has each server to the >> left in the ring is master to the slave to the right but I could see >> with intermittent networks down due to bad weather this could be a >> headache waiting to happen. Also the MySQL licensing has a degree of >> uncertainty to it so I would rather stay away. >> >> I am aware of PostgreSQL-R which is in beta, The uuid and timestamps >> available in web2py model help but then needs to be driven by cron in >> a batch oriented update. >> >> Sometimes I look at the NoSQL databases like CouchDB or MongoDB but >> then the foreign keys from the rapidly changing data is a problem. I >> could bridge it using equipment hostname or something like that but >> still I would rather stay inside one database. >> >> Hard problem to solve completely I think. >> >> Comments? >> >> Thanks >> >> Ron
