Either that or they have staff and infrastructure in place to deal with the lack of robustness. Yes, you need to be prepared to deal with corruption anyways, but the more robust your solution, the more time is left to deal with other things.

Over the years I have seen multiple instances of MySQL table corruption, index corruption and mysqldump exiting with a zero exit code after aborting mid-dump due to table corruption.

Of course I was prepared for this and I always had backups ready, but it was still time-consuming and annoying.

With Postgres I've yet to see any kind of data corruption even though my postgres usage is much heavier than my MySQL usage.

But this is why I said "anecdotal evidence": For me personally, Postgres has proven to be way more robust than MySQL. Is this my inability to properly administer MySQL? Is it me being unlucky with hardware (though Postgres is fine on the same hardware)? Is it me just being unlucky? I really don't know.

Popularity is not an argument for quality. See: crocs, Justin Bieber, PHP.

Those companies you mentioned, like many others, probably use it because they're locked in that technology, not because it's a superior one. Just like banks still use COBOL.

If you're interested on knowing why using MySQL isn't a good idea, there's this (highly opinionated, obviously) post about it: http://grimoire.ca/mysql/choose-something-else

What I am saying is that if MySQL wasn't robust then those companies simply wouldn't be using it. Since at their scale any bug or weakness will manifest at a level far greater than say at a startup. And they have the skills, time and money to choose any technology they wan't so I don't buy your argument that they are "locked in". Some like Facebook and LinkedIn have even created their own databases.

And I never said MySQL was a good idea. You did. I am saying that to claim it is not robust flies in the face of available evidence.

I'd tend to think your statement:

"And if MySQL wasn't robust then YouTube, Facebook, Twitter, Alibaba, LinkedIn etc wouldn't be using it for core parts of their infrastructure. It's definitely robust."

..points out that many (popular) sites use it, and a prerequisite is robustness, which thesaurus-wise, sounds a lot like quality.

I get that

a) you didn't actually say it, and

b) you could mean something much more specific, such as "companies with many highly-starred, complex open source projects which have also re-written major parts of their tech stack, but chose to leave mysql in place".

I know thats a bit more verbose, but it just seems to obviously close to the other author's interpretation with the ambiguity of the statement.

threeseed's argument is not

    this handful of popular companies use it, therefore it is good

    this handful of companies, each of which is considered by some/many to be 'excellent' or 'top', use it, therefore it is good

That conclusion does not follow from the premises: that some well known large companies use a technology in no way implies that it is robust.

You are assuming that large, well known companies always intrinsically select for high robustness in their tools, which is not necessarily the case. In fact, there are many well known public cases of the opposite.

It could be (for example) that large companies simply have the spare organizational capacity to deal with a lack of robustness. Perhaps they are locked in and find the ongoing cost of dealing with lack of robustness to be lower than the costs of switching to something more robust. Or it could be that they don't notice, for whatever reason, the lack of robustness. There could be many other possible explanations.

I am glad you mention the word "evidence", since you have provided none so far. An assorted selection of popular, buzz-worthy sites does not qualify as evidence (or lack thereof) of the validity of the technologies they use and endorse.

For contrast, I linked to a really nice post that explains thoroughly why MySQL is not a good idea in the slightest. I would encourage you to read it.