autovacuum causing numerous regression-test failures

I think we shall have to reconsider that patch to turn it on by default.
So far I've seen two categories of failure:

* manual ANALYZE issued by regression tests fails because autovac is
analyzing the same table concurrently.

* contrib tests fail in their repeated drop/create database operations
because autovac is connected to that database. (pl tests presumably
have same issue.)

There are probably more symptoms we have not seen yet.

In the long run it would be good to figure out fixes to make these
problems not happen, but I'm not putting that on the must-fix-for-8.2
list.

BTW, it would sure be nice to know what happened here:
http://www.pgbuildfarm.org/cgi-bin/show_log.pl?nm=wasp&dt=2006-08-28%2017:05:01

LOG: autovacuum process (PID 26315) was terminated by signal 11
LOG: terminating any other active server processes

but even if there was a core file, it got wiped out immediately by
the next "DROP DATABASE" command :-(. This one does look like a
must-fix, if we can find out what happened.

regards, tom lane