Hi Sebastian, How are your primary keys defined? I'm assuming some type of auto generation -- table, sequence, or identity. If I remember right, MySQL supports Identity id generation. In that case, I would let MySQL determine the synchronization across the clusters for the primary key generation.
Good luck, Kevin On Mon, Jan 14, 2013 at 6:04 PM, seba.wag...@gmail.com < seba.wag...@gmail.com> wrote: > I think I found what I was searching for: > > http://openjpa.apache.org/builds/2.2.1/apache-openjpa/docs/ref_guide_event.html#ref_guide_event_conf_tcp > > The RemoteCommitProvider must be set up and notify the other instances to > have a cache synchronization. > > I am not sure about the primary key issue yet, I guess there must be some > kind of solution to let the database-cluster manage the sequences/pk's, so > that multiple instances can write to the same database-cluster at once > without primary key duplication/constraint errors. > > Thanks > Sebastian > > > 2013/1/15 seba.wag...@gmail.com <seba.wag...@gmail.com> > > > Hi, > > > > we are currently drafting/implementing some clustering mechanisms for > > Apache OpenMeetings. > > > > I have seen OpenJPA supports the MySQL Replication feature: > > > > > http://people.apache.org/~mikedd/nightly.builds/apache-openjpa-2.3.0-SNAPSHOT/docs/docbook/manual/ref_guide_dbsetup_dbsupport.html#ref_guide_dbsetup_dbsupport_mysql > > which is great! > > > > However it solves only one side of the cluster: Having the database > > clustered. > > > > What happens if you want to cluster OpenJPA itself on multiple nodes? > Each > > OpenJPA instance would have its own data-cache, how can you make sure > those > > caches are synchronized across all nodes in your cluster? > > And how would you solve the primary key/sequencer issue? When multiple > > instances write to the same database they could potentially try to > create a > > record with the same primary key. > > > > Thanks! > > Sebastian > > > > -- > > Sebastian Wagner > > https://twitter.com/#!/dead_lock > > http://www.webbase-design.de > > http://www.wagner-sebastian.com > > seba.wag...@gmail.com > > > > > > -- > Sebastian Wagner > https://twitter.com/#!/dead_lock > http://www.webbase-design.de > http://www.wagner-sebastian.com > seba.wag...@gmail.com >
