PostgreSQL 8.4 released [LWN.net]

PostgreSQL 8.4 released

Posted Jul 1, 2009 23:13 UTC (Wed) by fdr (subscriber, #57064)
In reply to: PostgreSQL 8.4 released by Cyberax
Parent article: PostgreSQL 8.4 released

PGCluster is sort of in a weird place...certainly not among the most popular solutions. Consider slony (complex, well vetted) or londiste (part of Skype's skytools, mostly for aync multi-master replication)

Also, 'clustering' (which I take to also mean parallel query execution) is orthogonal to replication. Consider middleware, pl/proxy (also a Skype tool), or just old-fashioned hand-rolled application logic.

(Log in to post comments)

PostgreSQL 8.4 released

Posted Jul 2, 2009 1:29 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link]

Slony is asynchronous, and I need synchronous replication _and_ clustering.

I.e. two queries should return the same data if they are executed at the same time (of course, not considering other transactions), even if they are executed on different hardware nodes.

PostgreSQL 8.4 released

Posted Jul 2, 2009 4:00 UTC (Thu) by dlang (✭ supporter ✭, #313) [Link]

my understanding of mySQL is that their replication is not synchronous

for postgres, I think the option you would want is plproxy, it makes changes to all boxes in the cluster at the same time and splits queries between machines.

I haven't used it so check that it doesn't have any limitations that will kill you

PostgreSQL 8.4 released

Posted Jul 2, 2009 5:44 UTC (Thu) by fdr (subscriber, #57064) [Link]

You would be correct; MySQL's replication is asynchronous by in large. Much like Postgres there are some less-well traveled ways to acquire syncrep.

PostgreSQL 8.4 released

Posted Jul 3, 2009 20:27 UTC (Fri) by hingo (guest, #14792) [Link]

That is correct when talking about MySQL Replication. Google has developed "semi-synchronous" replication which should be in MySQL 5.4. Semi-synchronous is to say that changes are not applied synchronously, but data is copied to both masters so it can be considered safe/redundant.

MySQL Cluster on the other hand does provide synchronous replication, not to mention transparent sharding (scale-out) too.

Also for MySQL there are 3rd party solutions to do synchronous replication. I don't have enough experience to comment on those, I've seen people like them and dislike them all.