The size of an index (INDEX_LENGTH)

[Morten]

Hi,

I dropped an index on a table with 25M records today. The INDEX_LENGTH  
in information_schema.tables shrank from 3834642432 to 3215982592, ie.  
~618Mb difference

The index was on an int(11) column.

That means each index key takes up ~618Mb/25M ~= 25 bytes but that  
doesn't sound right? Is that true, or is information_schema.tables  
unreliable or?

Thanks,

Morten