PostgreSQL 8.4 will not produce a dump that restores to 8.1, as it’ll use features and syntax that do not exist in 8.1.
You might be able to downgrade by running 8.1’s pg_dump
against the 8.4 database, but it’s most likely that the dump will simply fail.
Downgrading that far will be a challenge and may involve hand-editing the dump produced by 8.4’s pg_dump
to make it 8.1-compatible.
8.1 is ancient and unsupported; its final end-of-life release was in November 2010. You shouldn’t even consider using it for any new project or tool, and really need to be planning an upgrade.
See the PostgreSQL version policy for just how different these versions are. You can learn more by reading the release notes for versions 8.2.0, 8.3.0 and 8.4.0. It is important to understand that application visible behavior changes are present in each release; you must test your applications and may need to enable some backward compatibility settings.
You should also read the upgrading a PostgreSQL cluster documentation—but be aware that pg_upgrade
can not be used to upgrade a version older than 8.4.
This would all be much less painful if your install weren’t seven years out of date.