On 08/06/2012 01:38 PM, Rajiv Kasera wrote:
Hi,
I am planning a Postgres migration from 8.4 to 9.1 to be able to leverage the replication features available in the 9.1 version. I would like to understand the following things in this regard:
1. Any good documentation which should help in this upgrade.
The most important documentation here is the release notes for the major .0 versions:
http://www.postgresql.org/docs/current/static/release-9-1.htmlhttp://www.postgresql.org/docs/current/static/release-9-0.html ... in particular the "Migration to" sections.
2. To be able to replicate the complete steps in a test environment before doing it in LIVE which is running 9.0, is it possible to revert this database to 8.4 and then upgrade to 9.1.
No. Take a copy before upgrading. Always. Keep the copy read-only in some safe place.
If you want to revert, make a copy of your backup and use that.
Upgrades from 8.4 to 9.0 or 9.1 require a dump and reload or the use of the pg_upgrade tool. You can't just install the new version and start it on your old database.
3. Any known issues and changes required to be done in the application for this upgrade.
See the release notes.
--
Craig Ringer