Seems to me that there are a bunch of agendas here.
I read about not wanting to be trapped into a proprietary system. You
can be trapped in any software you depend upon. Compilers, Platforms,
SCM, issue tracking are all places to be trapped.
Postgres and Postgresql have been around a very long time for the
software world. It has outlived several of the systems it has depended
upon over those many years. I hope and expect that Postgres will
continue to outlive some of these platforms.
So do not get hung up on having been 'burned' in the past. Expect to be
'burned' again. Take steps to minimize that pain in the future.
For an issue tracker, open source or proprietary, I would want raw
database dumps and schema information. Postgres is a database after
all. If you truly have the data, you should be able to migrate it.
Also, does the system you adopt use Postgres? You are your best open
source software. If performance starts to go downhill, you are in the
best position to fix it if you understand and control it. How
responsive will whatever system be to your changing needs? If you
partner with an external group, the two groups will benefit from each
other if they are truly sharing the technologies.
Jeff Anton