How to change temporary directory for pg_dump? I'm running out of space from my hard drive which has a 18GB PostgreSQL database.
When I try pg_dump to a different drive, PostgreSQL creates temporary files on the disk it's dumping from, so I run out of space and the dump fails.

I tried this from Stackoverflow and a small file is created in the new directory, but nothing else, and pg_dump still writes to the original disk.

How do I change temp directory for pg_dump?

Note: My work_mem setting is pretty high already, I can't change that.
My db version is 9.0.13.
The temporary files are a side effect of the --format=tar option.

A backup in default plain format goes through without temporary tables in the local drive. Omit the option to produce a backup in plain format without temporary local files.