Is really MySQL ACID compliant?
This is a really interesting question. Many people are force to think that MySQL is not totally ACID compliant due to some limitation of MySQL itself or limits introduced by some particular storage engine.
We cannot hide that old versions of MySQL were not aware of the concept to transaction and transaction is a concept must be present in an ACID database. Also ACID implying a good design of application and data, as said by Alex Popescu:
That’s because you are basically taking your data and vomiting it on the hard drive without any consideration as to if your data you are writing is sensible or simply dreamed up by magic pixies.
You may also find an interesting bug opened to MySQL: bug #62209. There is a nice complain about ACID functionalities when MySQL is used with InnoDB. Jordan Hall also made a simple test about the functionalities of CHECK constraints in MySQL showing that ACID is not totally supported.
At the end, this famous video: