After setting up 9.5beta2 on the Npgsql build server and running the Npgsql test suite against I've noticed some weird behavior.
The tests run for a couple minutes, open and close some connection. With my pre-9.5 backends, the moment the test runner exits I can see that all backend processes exit immediately, and pg_activity_stat has no rows (except the querying one). With 9.5beta2, however, some backend processes continue to stay alive beyond the test runner, and pg_activity_stat contains extra rows (state idle, waiting false). This situation persists until I restart PostgreSQL.
This happens consistently on two machines, running Windows 7 and Windows 10. Both client and server are on the same machine and use TCP to communicate. I can investigate further and try to produce a more isolated repro but I thought I'd talk to you guys first.
Any thoughts or ideas on what might cause this? Any suggestions for tracking this down?