[CentOS-devel] Upgrading postgresql (Re: CentOS/RHEL 5.3)

Thu Jan 22 18:39:53 UTC 2009
Joshua Kramer <josh at globalherald.net>

> So how do you package such a thing in RPM so it can permit both new and
> old instances to run simultaneously while you do all of this required
> testing?  I suppose these days virtualbox is an almost-reasonable answer

I think this discussion is a reflection of our different environments.  :)

On my websites... when 8.3 came out, I downloaded it to a test machine.  I 
then did a dump of the production data from 8.2, and did an import into my 
8.3 test machine.  After pointing an Apache dev instance at the test 
database, I could verify that my applications still worked, and make any 
code changes that were required.

After I had a test/dev environment that was stable under 8.3, I planned 
the migration: 1. Dump 8.2; 2. Shutdown 8.2 and remove packages; 3. Move 
8.2's data directory; 4. Install 8.3 packages, and initdb; 5. Import data 
made during the dump and start db; 6. Migrate code changes to web server. 
After things baked for a week and there were no errors, I deleted the old 
8.2 data directories.

I realize that this is much more difficult if you're using a VM on a web 
host that only allows one machine.  Is this the type of environment that 
is constraining you?  As long as you can test your application under the 
new database version to make sure it's OK, the migration can be done on 
one machine.  But let me ask: in what case would you not want to test your 
application against a new database version?



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