mySQL integer types

[Bob Sneidar]

Hi all.

I am a little bit concerned with defining integer types. The manual defines INT as using 4 bytes for storage, for a maximum of 4294967296 values. However, I read somewhere (possibly here) that for auto incrementing keys I should use int(64) the maximum allowed. Does that mean that my storage for these values will use 64 bytes for each record? That seems like overkill of overkill. 

I do however want to ensure that no matter how long my application runs I will never exceed the maximum value in an auto-incrementing column. There has to be some kind of balance here. Any ideas? I have tried looking for information on ways to reset the AI value of a table, but it seems by all accounts this is not allowed. I had hoped that if I did so, mySQL would simply find the lowest unused value each time, but I guess it doesn't work that way. 

I can do that myself with a query, but the simple way would be to make sure I have enough values that I will never run out. 

Bob