On 2010-04-22, Brian Peschel <bri...@occinc.com> wrote: > > On 04/22/2010 10:12 AM, Ben Chobot wrote: >> On Apr 21, 2010, at 1:41 PM, Brian Peschel wrote: >> >> >>> I have a replication problem I am hoping someone has come across before and >>> can provide a few ideas. >>> >>> I am looking at a configuration of on 'writable' node and anywhere from 10 >>> to 300 'read-only' nodes. Almost all of these nodes will be across a WAN >>> from the writable node (some over slow VPN links too). I am looking for a >>> way to replicate as quickly as possible from the writable node to all the >>> read-only nodes. I can pretty much guarantee the read-only nodes will >>> never become master nodes. Also, the updates to the writable node are >>> bunched and at known times (ie only updated when I want it updated, not >>> constant updates), but when changes occur, there are a lot of them at once. >>> >> Two things you didn't address are the acceptable latency of keeping the >> read-only nodes in sync with the master - can they be different for a day? A >> minute? Do you need things to stay synchronous? Also, how big is your >> dataset? A simple pg_dump and some hot scp action after you batched updates >> might be able to solve your problem. > > Latency is important. I would say 10 to 15 minutes max, but the shorter > the better. I don't have an exact size, but I believe the entire DB is > about 10 gig.
should not be a problem 10 to 15 second latency is easy to get over slow connections (eg satellite) with any of the proposed solutions. > We had an idea of creating our apps write the SQL statements to a file, > rather than using an ODBC drive to directly change the DBs. Then we > could scp/rsync the files to the remote machines and execute them > there. This just seems like a very manual process though. yes, and furthermore SQL-replication tends not to work as intended if you have any updates or inserts that invoke non-constant default values like now(), nextvalue(...), or random() -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
