On Thu, 2006-09-21 at 17:30 +0200, Bo Lorentsen wrote: > Hi ... > > I have been trying to find a replication to a payment system at the > company I work, and Slony-I is of cause the first thing that game into > my attention. But when reading chapter 23.3 in the PG manual, there is > this comment of PITR used as a replication tool. > > I also saw the "pgpitrha" project, and this sounds really nice too, but > is this a good way to go ? Will PITR be more replication friendly > in the future or even form the basis for a future buildin async > replication form ? > 8.2 makes PITR much easier to use for the situation you'd like. In 8.1, a WAL might sit around for a while before it becomes full and then sent off. 8.2 allows you to force a WAL to be sent, and it also allows a standby mode. Slony is a good system now, and it's nice because you can use different versions of PostgreSQL. PITR requires that it's the same version. However, if you're working with a payment system or accounting system, you may need synchronous replication. With any asynchronous solution (Slony or PITR standby), there is a possibility (although not likely) to lose *committed* transactions. If you do need synchronous replication, consider using two-phase commit to prepare transactions on several machines before committing them. This ensures that the data will be on multiple machines before committing to any of them. Regards, Jeff Davis
