young guy wanting (Postgres DBA) ammo

Hiya list,

A friend recently told me that, among other things, the institutions for
which he works tend to choose MySQL or MSSQL over Postgres because the
latter requires a dedicated DBA while the former do not. When they do
spring for a DBA, they go with Oracle. As a developer/end-user in/of
the MySQL/Postgres/Oracle environments, I can say hands down that I
prefer Postgres and I have a list of reasons why to which I can readily
refer.

However, I'm not a DBA and only minimally know what's involved in doing
the job, so I don't have "ammo" to defend (or agree?) with my friend
when he says that "Postgres requires a DBA and MySQL doesn't so that's
why they choose the latter." Basically, I have so far not run across
the need to mess with any of the tunables. (I am naive, I know.)
Clearly, one should generally pick the best tool for the job, so I'm no
pundit that Postgres is *always* the right answer, but I'd like to be
informed. My questions:

- With 8.2, and the almost-out 8.3, what kinds of responsibilities
should a Postgres DBA expect to have?

- More in line with the conversation with my friend, what/why is it that
Postgres needs a DBA while MySQL doesn't? I highly suspect that the
assumption that MySQL doesn't need a DBA is incorrect, but that's what
was posed to me and I couldn't agree or disagree.

I am familiar with Greg Smith et al's page:
http://www.postgresql.org/docs/techdocs.83

Thoughts? Thanks in advance,

Kevin

P.S. BTW Greg et al, thank you a *ton* for putting that document
together. I learned a lot watching the discussion on the list and
reading the final version.