How to convert Postgres from 32 bit to 64 bit
You can't use pg_upgrade for this, as it can only upgrade clusters from versions that are built with the same options on the same architecture. You must either:


dump and reload, with the associated down-time; or
Run both the 32-bit and 64-bit versions concurrently and set up a 3rd party replication tool like Bucardo, Londiste or Slony-I to stream rows across. Once they're in sync, stop the 32-bit DB and remove the replication.


Also, there's no PostgreSQL 8.5. Did you mean 8.4? "v9" isn't very specific either - PostgreSQL 9.0, 9.1, and 9.2 are all quite distinct releases. See the version policy, which outlines PostgreSQL's quirky versioning.