Re: Major performance problem after upgrade from 8.3 to 8.4

Gerhard Wiesinger <lists@wiesinger.com> writes:
> BTW: I have the old data setup. /var/lib/pgsql-old. Is there a fast setup
> with old version on different TCP port possible to compare query plans?

You'll need to reinstall the old executables.  If you put the new
executables in the same directories, it's not going to be easy to
run both in parallel.  If you didn't, then you just need to start
the old postmaster using a different port number.