Re: unable to pass variable PGDATA2 into server environment

Hello list,

On Thu, Jul 01, 2004 at 01:55:19PM -0400, Tom Lane wrote:
> Jean-Christophe Weis <jcweis(at)melix(dot)net> writes:
> > The variable PGDATA2 is set and marked for export in the root shell where I
> > start the server, but it is not passed into the server's environment.
>
> No, because the start script is going to su to the postgres account,
> and su is going to reset the environment. The usual advice for doing
> this sort of thing is to set the environment variable in the postgres
> user's .profile file. That way the postmaster has it, and you also
> have it if you manually su to postgres.
>
> (This whole benighted environment-variable scheme is gone in CVS tip,
> thank goodness.)
>
> regards, tom lane
>
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I did not think that su might reset the environment as Tom says, because I had
seen:

| root# PGDATA2=/home/jc/postgres/data
| root# export PGDATA2
| root# su postgres
| postgres$ echo $PGDATA2
| /home/jc/postgres/data

and also because '/path/to/initlocation PGDATA2' worked in the 'postgres'
shell.

But after Tom's remark, I wanted to have a closer look at my
'/etc/init.d/postgresql' script, and this is what I saw:

| startup () {
| ...
| su - postgres -c /usr/lib/postgresql/bin/postgresql-startup
| ...
| }

There is a dash after 'su'. And this what 'man su' says:

| The optional argument - may be used to provide an environment similar to
| what the user would expect had the user logged in directly.

That is to say, my problem was that the variable PGDATA2 was set and marked
for export in the root shell where I started the server, but it was not passed
into the server's environment _because_the_init_script_does_a_'su dash'_.

When I delete the dash in the init script, I can create a database in the new
data storage area as described in the documentation:

| jc$ createdb testdb -D PGDATA2
| CREATE DATABASE

And if I let the dash in, and follow Tom's advice of setting (and marking for
export) the PGDATA2 environment variable in the postgres user's '.profile', it
works fine too. (I had a hard time finding that the home directory for the
postgres user was '/var/lib/postgres'...)

So, thanks to the list, thanks to Tom and thanks to Guido Barosio too, who
answered me directly. So long,

--
JC Weis <jcweis(at)melix(dot)net>