clarify a bit...
For starters, the driver itself is linked against the PG client
library, with the appropriate path information to find the given
installation data etc. To run two versions, you need two .so files.
On my system I have postgres.so and postgres7.1.so to run PG 7.0 and
7.1. I simply configure the right driver in my "/ns/db/drivers"
section and OpenACS 3.1 works fine.
The package loader for ACS 4x needs to be able to run PSQL directly,
as well as access the driver. This means that you need to give
OpenACS 4x two separate paths the the PG binaries to run two versions.
This is where the new config param Dan alludes to comes in. I
"invented" a new /ns/db/driver/postgres param called "pgbin" that lets
you specify the path to the directory containing PG binaries. At the
moment only PSQL is needed.
At the moment OpenACS 4x ignores your PGPATH and other environment
variables, which means you *must* supply the "pgbin" config param.
I'll clean that up after I get the APM working for both Oracle and PG,
since it's really just a convenience, not a showstopper.
Pascal - since you've offered to help with documentation, if you are
planning to run OpenACS 3.2+PG7.0 and OpenACS4x+PG7.1 on the same box,
would you be willing to write up what's needed in a more presentable
form? I'll be more than willing to help you through any sticky spots
you hit while trying to get things configured and running ...