I'd like to know what the age of the oldest running transaction is.
i.e. hunt look out for old idle in transaction transactions that are
holding up vacuuming.
Info on the shared buffers like % used, % that hasn't been updated or
seen in x minutes / hours / days.
% used on various tablespaces
connection stats: how many clients connected, by what accounts, %
failed auths, stale connections harvested by tcp_keepalive timeouts...