Victor Wagner wrote: > Rationale > ========= > > Since introduction of the WAL-based replication into the PostgreSQL, it is > possible to create high-availability and load-balancing clusters. > > However, there is no support for failover in the client libraries. So, only > way to provide transparent for client application failover is IP address > migration. This approach has some limitation, i.e. it requires that > master and backup servers reside in the same subnet or may not be > feasible for other reasons. > > Commercial RDBMS, such as Oracle, employ more flexible approach. They > allow to specify multiple servers in the connect string, so if primary > server is not available, client library tries to connect to other ones. > > This approach allows to use geographically distributed failover clusters > and also is a cheap way to implement load-balancing (which is not > possible with IP address migration).
I wonder how useful this is at the present time. If the primary goes down and the client gets connected to the standby, it would have read-only access there. Most applications wouldn't cope well with that. Once we have multi-master replication that can be used for fail-over, the picture will change. Then a feature like that would be very useful indeed. > "host=main-server host=standby1 host=standby2 port=5432 dbname=database" It seems a bit arbitrary to require that all servers use the same port. Maybe parameters like host2, port2, host3, port3 etc. might be better. Yours, Laurenz Albe -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
