As long as we're talking about different open source databases, there's
also SAP DB (
http://www.sapdb.org/). This is a once-commercial database
that is now under open source, similar to Netscape/Mozilla. As this once
was commercial, running databases for the largest companies, it seems to
outclass both MySQL and PostgreSQL in speed, reliability, and supported
SQL language. The strange thing is that it is hardly known in the open
source scene. I didn't try it myself yet, either.
Anyone willing to give it a try? (I'm busy with something else right now...)
Magnus