We have our production environment database server in Postgres 8.3 version. we have planned to upgrade to lastest version 9.1. Dump from 8.3 and restore in Postgres 9.1 takes more than 5 hours. Any other quick method to upgrade from 8.3 to 9.1. We need to reduce our downtime below 1 hour. Any Possibilities..?
You should consider 9.2.. Ofcourse, you need to test your application against 9.2 before migrating, because as you mentioned you are on 8.3 where you application might be compatible to it. There are some changes to functions,string handling etc which are more advanced in 9.2. Once you agree that app.. is good to go with 9.2, now to think for option with less downtime or affordable downtime.
I would say, use pg_upgrade which has minimal downtime. I guess pg_uprades supports from 8.3 onwards.
If you say no downtime or even minimal then prefer Slony-I (trigger based replication).
