Sorry, but your question seemed naive and still seems so. I was actually
hoping to hear my understanding of your concern was wrong.
There are thousands of web sites, big and small, using mysql and postgresql.
They all have bugs, just as any Linux or another other OS we choose has
bugs, some big, some small.
Oracle has bugs as well - some as serious as found in any major open source
database project.
This inability to install a database is not a real inability, but rather
an irrational choice. If mysql was seriously flawed, then it should
surely fall
apart under the weight of its use to power facebook.
If the facebook example seems like a one hit wonder, take a look at the
other
"customers" of mysql:
http://www.mysql.com/customers/
If stability is your concern, don't run with Sid. It is for development
work and
testing changes. People might run Sid on the desktop for getting slightly
later and greater packages, but Sid is not for production use.