so that in case you need to do a hard restore (if you’re going from postgis 1.x to 2.x) you can run the dump file through the special cleaning script.
See postgis documentation notes on “hard upgrade” for full info on doing a clean 1->2 upgrade.
If he’s already blown away his old environment then yeah, you’re going to have to exactly duplicate it first so you can run 8.4 *and* an old version of postgis (have to match major version numbers) and get a clean dump file out of it.
P.
Yeah, that perl script really works well, used it a lot.
Only downside is the downtime you need for it, on servers that is.
I really like pg_upgrade, and i have been able to use that since apt.postgresql.org offers several versions per distro, and includes postgis too.
Great stuff, upgrade a big db in single minutes of downtime.