physical table size

[Marek Puchalski]

I have created a database using some innobase type tables. I had to fill my database with quit a lot of data, to test its efficiency. I have also made calculations of how big my database will be. After calculating the data size (well, you know... INT = 4B, DATE = 3B, VARCHAR(x) = k+1 and so on), I came to a conclusion, that my database will be about 62MB big. (This calculations are quite accurate.)

But my MySQL Administrator tool says, that my database is about 90,2 MB big. The indexes use 11,8MB. Well: 90,2-11,8-62 = 16,4 [MB] of space. That's quite a lot... (18% of the database size). What is MySQL using this space for? Is the innobase type really so spaceconsuming? Where can I read more about it?

...

Yes, I am a student. :)

Best regards

Marek