The following bug has been logged on the website:
Bug reference: 8589
Logged by: Tom Yan
Email address: tom(dot)ty89(at)gmail(dot)com
PostgreSQL version: 9.2.4
Operating system: Windows 7 x64
Description:
What I do is to pipe pg_dump -Fc to python's subprocess stdout.
The dump file I got is still usable with pg_restore, just it's not
compressed. It doesn't work even if I add -Z option manually.
And this is likely not a python's issue since the I can have compression
with -Z if I choose to export plain sql.