Postgresql the right tool (queue using advisory_locks + long transactions)

Hi list,

I am trying to use postgresql as a queue for long-jobs (max ~4 hours) using
advisory_locks. I can't separate the long-job into sub-jobs.

1. At ultimate-best-case scenario there will be ~100 workers, so no
web-scale performance required.
Is there a problem with 100 open sessions (behind a connection pooler?)
for hours like in my case?
The session will commit the progress of the job, but will stay opened
and hold the advisory_lock till the job is done or it expires (look 2).
2. Is it possible to set a time limit to auto-close an opened session
that hasn't made a query in a while ?
So if a worker fails,and the session time-outs, postgresql/pgbouncer
will close the session and release the lock ?