Disadvantages of MySQL versus other databases

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Every single book that teaches programming (or almost anything else) starts off with a whole bunch of spiel on why what it's about (C++, MySQL, waterskiing, skydiving, dentistry, whatever) is the greatest thing in the world. So I open the MySQL O'Reilly book, and read the intro, and get the traditional sermon. The main points that the book mentioned were:

  • MySQL has been shown to have tied Oracle as the fastest and most scalable database software.
  • It's free and open source.

Sounds pretty convincing, but I know there's always at least two sides of every story. I knew I needed to be disillusioned when I saw someone suggest to someone to use Oracle instead of MySQL and thought, "Why in the world would you want to do that?!", just because of the few paragraphs I'd read, with no other justification. So lets investigate the other side of the story:

What are some reasons NOT to use MySQL?

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18 Answers

MySQL can certainly match or beat Oracle in speed. I've done it numerous times myself. Ok, so I had to use various table types like black hole, merge, innodb, and myisam in just the right laces. And it took me a few days to get everything working just right. The Oracle DBA got things working in an hour or two.

MySQL is fine for 98% of the sites out there, maybe more. But it is fairly easy to bring it to a crawl without a lot of data if you don't know what you are doing. Oracle is quite a bit harder to bring to a crawl, but it can still be done. I've worked with both with datasets in the hundreds of millions of records (tiny by some measures). MySQL takes quite a bit more attention.

No database can scale indefinitely, which is why nosql "databases" are becoming so popular. I think the real question is if MySQL is "good enough" for what you need to do. The price is certainly right. The same could be said about PHP.

Why does Facebook use MySQL? Could you imagine what it would cost them to buy enough Oracle licenses!? It's good enough.

user_1512690

MySQL is very tolerant of ambiguities -- something you don't want in a database system. Here are a few examples off the top of my head:

  • As another poster stated, CHAR and VARCHAR columns are case-insensitive, already a pretty bad sign.
  • You can INSERT into a table that has a column without a default value that is also NOT NULL. Yes, really! Instead of throwing an error, MySQL will pick a value for you based on the data type, e.g. 0 for numbers.
  • You can use a GROUP BY statement while some columns are neither using an aggregate function, nor included in the GROUP BY statement. The outcome is pretty much random. No warnings or errors here either, in my experience.

MySQL is also far from rock-solid. Just this month, I discovered a bug in the (admittedly old, but a "stable release") version of MySQL used by DreamHost that results in data loss. (Certain conditions when creating a table with variable-length rows.)

I've been using MySQL for many years and still do, but would never dream of using it for anything serious, where data loss would be a big problem. It's great for non-mission-critical web sites and blogs though.

user_1289470

It's free and open source.

True. But keep in mind that MySQL is, in many cases, not free for commercial use. MySQL and the connectors (the official drivers for various languages), are GPL licensed.

If you use, say, the Connector/.NET to connect to MySQL your code have to be GPL compatible. It's dual licensed though, so you can buy an enterprise version under another license - and I believe they have a (either free or just very cheap) program that lets you license the connectors under a different license.

Everyone I know using MySQL is unaware of this :-)

user_1574040
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