Re: youtube and facebook do not care about ACID.
"Facebook doesn't care about you losing a few wall updates. If you care, well, why don't you just post them again?"
Assumption on your part in that A) They don't care, B) Any lost wall updates are due to MySQL, can you back that up?
Although to be fair I also assume that they do care about their data, others can judge which assumption is more likely
"Youtube cares more about Big Content[tm] farting than the "rights" of their freeloading users. Case in point: Complain-bots that get birdsong deleted as copyright infringment; the DMCA requirement the actual holder to the rights needs to complain is dead letter to them."
You are totally going off-track here, this is about MySQL, not copyright enforcement.
"You need no ACID to keep track of that sort of content, nor the other user contributions that come with it. "You wouldn't want to run payroll on those systems,"
And yet financial companies do use MySQL for mission critical applications. A single example found via google.
http://www.mysqlconf.com/mysql2009/public/schedule/detail/6235 . Of course you could just say that they do not know what they are doing but then it is basically your opinion vs theirs.
"but that doesn't stop millions of people happily using them for other purposes. My point was about the former, and your counter with the latter is frankly orthogonal."
Your original point, as far as I can read, was, in a nutshell that 'MySQL Sucks and so does all its fanbois' and that anyone using it does not have "half a clue about database theory and who values their data"
At no point did you offer a caveat that it was suitable for certain situations by anyone with "half a clue". That, combined with your use of language is what made me say it was a rant rather than a reasoned discussion.
"Being big is no guarantee for good practices. It's easier to argue that good practices are more expensive the bigger you get, especially if you have to introduce them after you've grown big."
Very true, however when 'big' fails, which you imply is an inevitability with MySQL, it usually makes headline news in the tech world and to be honest, I cannot really remember any "Holy crap, $BIG_SITE irrecoverably mangled all it's data and it was conclusively proved to be due to MySQL's crappiness."
"So much so that it was easier and cheaper for facebook to hire a crack team of C coders and have them build a php-to-C translator to speed up running the steaming pile of php mess that is the core "IP" of the business, than it is to actually re-architect and re-factor it into something resembling "good practices"."
What has language choice got to do with best practices? Again, your prejudices (this time against PHP, which to be honest, I rather share) is getting in the way of making a reasoned argument, and again you make the assumption that the facebook code is a "steaming pile of php mess", unless you worked there or seen large parts of the source-code, you are in no position to comment.
"There's plenty of people who know their stuff at big companies, even if it doesn't show for this reason or that. It's the "and who value their data" that's tripping you up: These molochs do not, in fact, care much about any individual's data. It just needs to not leak too much lest too many people take notice, is all."
Again, an assumption that they do not care about their data (With another derogatory term thrown in for good measure.) with no supporting facts.
And finally, I said "large companies like Youtube and Facebook". There are plenty of large companies out there that use MySQL in mission critical situations (Where I imagine ACID compliance is rather important).
If you posted some supporting evidence about why the latest version of MySQL sucks you might actually convert some people. As it is, you just come off as someone ranting hence my original reply.