Markus Schiltknecht wrote: > Hello Bruce, > > Bruce Momjian wrote: > > Uh, I think of PgCluster as multi-master, but in a way it is a hybrid > > because there is a central server that gets all the queries. > > Yes, PgCluster as well as Sequoia use statement based replication. > Sequoia is also clearly a middleware (no changes to Postgres needed). > > Both suffer from the limitations you describe in "statement based > replication middleware". AFAICT Sequoia does quite well in circumventing > those. (Heck, it even tries to masquerade differences between database > systems, so you can keep a Postgres database in sync with a MySQL one.) > > Depending on the RAIDb level you are using, Sequoia can be considered > multi-master (RAIDb-1) or single-master (RAIDb-0). Also note that > sequoia can run multiple controllers, thus it does not rely on one > central server.
But in those cases isn't the multi-master just at the storage level? I don't consider that multi-"master". > So, at least Sequoia is clearly a hybrid, in between your definitions of > "statement based replication middleware" and "synchronous multi-master > replication". Depending on how "middleware" you consider PgCluster, it's > also a hybrid. Certainly it does statement based replication. I am afraid we are stuck between clarity and understand-ability here. ;-) -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://postgres.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
