Re: How do I get mysql to use the keys?

[Ingo Strüwing]

This is not a MyISAM question, I guess.
I can only speculate about what the optimizer does.
In the first query, the BETWEEN is used in an unusual way. The optimizer might not be designed for this type of query (yet).
Your primary key is the concatenation of two integers. For a range scan it would be possible to use a condition on the first part of the key only. In your second query it would mean to start the table scan at the position where ipFROM>=1142156934 until the end of the index. But if this is a big part of the index, it might be faster to scan the data file only, instead of scanning the index and pick the corresponding data rows by random access. I think this is indicated by 'possible_keys' = 'PRIMARY' and 'key' = 'NULL'.