On the other hand, commercial vendors like Oracle and open source projects like PostgreSQL recognize their role as database engineers is to first and foremost "do no harm." Ie, the database should never destroy data, period. Bugs that get released that do cause such things can be traced back to issues that are not related to a reckless pursuit of other priorities like performance. Watching the PostgreSQL engineers agonize over data integrity and correctness with any and all features that go out that are meant to improve performance is a re-assuring sight to behold.
This priority list goes without saying for professional database engineers. That there is such a 'tension' between stability and speed says less about a real phenomenon being debated by database engineers and more about the fact that many people who call themselves database engineers have about as much business doing so as so-called doctors who have not gone to medical school or taken the Hippocratic oath.
But I think a major difference between MySQL and Redis, MongoDB, Cassandra, and all the other NoSQL solutions out there is that MySQL had an impressive test bed: all the GPL LAMP applications, from forums to blogs, shipped and users by a shitload of users. We miss this "database gym" so these new databases are evolving in small companies or other more serious production environments, and this creates all the sort of problems if they are not stable enough in the first place.
So what you say can be more important for the new databases than it was for MySQL indeed.
And if MySQL never existed, what would have happened ? Would we have all used PostgreSQL in the first place and avoided years of painful instability ?
I read here all the time that fashion and ease of use are more attractive than reliability. And we introduce plenty of new software in complex architecture just because they are easy to use. We even introduce things like "eventual consistency", as if being eventually consistent was even an option for any business.
The problem is to not use random datastores. Use a database that has a proven record of stability. And if someone builds a database, he/she must prove that ACID rules are taken seriously, and not work around the CAP theorem with timestamps...
10 years ago, MySQL was not stable. PostgreSQL was. Today, most key-value databases are not stable, PostgreSQL is.
My sense was that it got a pretty thorough review and revision/rewrite in the transition from Postgres to PostgreSQL.
The change from Postgres to PostgreSQL was largely a UI/API change and the move from QUEL to SQL. However, over time virtually all of the software has been reviewed and rewritten. It's an excellent project, and I have been using it since 6.5.......
Most key-value databases didn't prove (as in: show me actual resistance tests, not supercompany123 uses it) that they are reliable. The day they do, I'll be the first one to use them. Until then, it's just a toy for devs who don't want to deal with ER models.
Then again, Postgres -- the project -- did not try to position itself (was there even such a thing as "positioning" for Postgres 16 years ago?) as a mature, stable project that one would credibly bet one's business on.
Lots of early database releases are going to be like Mongo, the question is how much the parties at play own up to the fact that their implementation is still immature and present that starkly real truth to their customers. So far, it seems commercial vendors are less likely to do that.
However, actually-not-a-terrible-idea is pretty relative, when you look at how the industry has evolved in the mean time. I mean, compared to MySQL at the time, PostgreSQL 6.5 was really not a terrible idea. 7.3 was the first release I didn't have to use MySQL as a prototyping system though.
And with 9.x things are getting even better.
I think you're missing the point a little. Yes, MySQL is a heap, and having to work with it in a Postgres world sucks. But, the point antirez is making in that comment (at least how I read into it) is that an active user community in ANY project is hugely important in that project's formation and "maturity" (sarcastically, of course, because Postgres is clearly more mature than MySQL). There's no extrapolation here to the top-level Mongo discussion going on in this thread -- I was just clarifying antirez's point.
I know benchmarks don't put this quite as fast as 5.5, but there are still possible gains to be made.