Re: dump from 8.x restore to 7.3.x

> We have a pretty big database that is going for an upgrade (PG7 -> PG8)
> in the next few days, we have tested all the features of our application
> but we cannot be sure that everything will work out perfectly (db is
> managing several blob's only tables that have proven to be pretty hard
> to configure).
> I am currently investigating a worst-case-scenario strategy that would
> be to downgrade the database from PG8 to 7 if anything goes wrong;00
> this implies that we:
> 1) dump from a running PG8
> 2) remove PG8 and reinstall PG7
> 3) restore the dump into the running PG7
>
> unfortunately pg_restore complains about the dump header and doesn't
> restore the db at all, having tried to dump with both -Ft and -Fc flags
>
> shall I try the "--ignore-version" option in pg_restore?
> is there going to be any problem in using this option? (corrupted data,
> tables, etc.)

My understanding is that dumps are not backwards compatible. Any dumps created with a Version 8.*
pg_dump cannot be used for any older versions. If you want "play it safe" you should create a new
server for the postgresql version 8.1 to preform validation tests with your front-ends. After you
are satisfied that everything works well you can replace the version 7 production server with
version 8.

If you would like a safety net beyond this you could contact one of the PostgreSQL consulting
companies to walk you through the integration of V.8.1 into your projection system.

Regards,

Richard Broersma Jr.