I notice that in 8.3, when I kill the postmaster process with SIGKILL or
SIGSEGV, the child processes writer and stats collector go away
immediately, but the autovacuum launcher hangs around for up to a
minute. (I suppose this has to do with the periodic wakeups?). When
you try to restart the postmaster before that it fails with a complaint
that someone is still attached to the shared memory segment.
These are obviously not normal modes of operation, but I fear that this
could cause some problems with people's control scripts of the
sort, "it crashed, let's try to restart it".
--
Peter Eisentraut
http://developer.postgresql.org/~petere/