Jeff Frost wrote: > On Tue, 14 Nov 2006, Bruce Momjian wrote: > > >> My thinking on the definition of clustering was that there is some smarts > >> for > >> graceful failover and automated or semi-automated ways of bringing failed > >> DB > >> servers back up to date and online with the rest of the servers in the > >> cluster. All servers need to be able to accept writes, but do we > > > > No, even replication servers can have that. > > > >> differentiate on where the writes originated (i.e. middleware or another > >> postgresql server) or on functionality? > > > > Fundamentally, broadcast means the queries are being propogated outside > > the server, with the benefits and limitations inherent in that. > > I'd definitely have to agree with you on that. I guess I'm trying to decide > what differentiates clustering for load balancing from query broadcast based > on your text. Maybe just don't use the word broadcast here: > > "In clustering, each server can accept write requests, and these write > requests are broadcast from the original server to all other servers before > each transaction commits." > > Unfortunately, I can't seem to come up with anything more clever.
Basically, when you are broadcasting outside the server, you are broadcasting SQL queries, and those queries do not have information about non-deterministic functions and have issues with universal commits on all node. I think I now see your point about using the word "broadcast" for both clustering and middle-ware broadcast. Let me find some new wording and repost. -- Bruce Momjian [EMAIL PROTECTED] EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
