Re: disk format changes

Craig Isdahl wrote:
> Hello to Everyone,
>
> First, I'm new to postgres and fairly new to Linux (redhat).  Really
> love what I've seen of postgres, and this list so far.  It is
> obvious there is a lot of experience on this list.
>
> In the weeks I've been following this list I've only seen one
> reference to my question, and I wasn't able find anything in the
> docs.
>
> Why does the on disk format of postgres change between major (not
> sure if that's the right terminology) releases?  Benefits?
> Drawbacks?
>
> As someone new to the "scene" the thought of "dumping" databases,
> running initdb, then restoring the databases is... umm... (looking
> for the right word)... daunting/scary/silly.  Especially for
> production dbs.
>
> However, I've also noticed that many on this list are running some
> "serious" postgres installations and this apparently isn't a
> concern, so I thought I'd ask.

I did write a pg_upgrade utility for 7.2 in /contrib that allows
upgrades without dump/reload.  Unfortunately, the changes for the
compressed transaction log cause it to fail, and I didn't have enough
time to get that part working.  Hopefully it will work for 7.2->7.3
changes if I can make sure it transfers over all the data correctly.

So, we do know this type of utility is needed.  I just hope we can pull
it off, because each release has different changes.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
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