Richard Broersma Jr wrote:
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.
I don't see that as being the case - there will be exceptions where you have new features in an 8.x database that won't work in a 7.x db but otherwise it shouldn't matter, the dumps can be used to import into other databases than postgres as long as you use dump with inserts instead of copy and use common datatypes.
I would expect that if you dump from 7.x into 8.x and have issues then a dump from 8.x into 7.x would work as long as you haven't changed your schema to add 8.x only features.
If you have any concerns and want a fall back safety net, then you will want to either not add any 8.x features or document the changes so that the structure can be changed back to be 7.x compatible.
Of course not making any schema changes until you are happy to stay with 8.x will help and you could just dump data only to go back.
-- Shane Ambler pgSQL@xxxxxxxxxxxxxxxx Get Sheeky @ http://Sheeky.Biz
