Where does MySQL “store” table overhead data?

Question

I'm about to move a large database table away from my production server for backup.

~130,000,000 rows, 45GB total data.

After an interupted DELETE query (during the update process) the table now has an overhead of over 100MB.

From past experience I can't optimize this table on my production server without impacting on the perfromance of my live site.

So I plan to move the table to another server.... I always take the .frm, .MYD and .MYI files...

But where is the overhead stored? In the .MYD? And do I need to bring overheard data with me if the table will need to be rebuilt anyway?

Answer 1

Overhead is space in the data files that used to contain data but doesn't anymore (due to DELETE queries etc.). If you can't optimize, you're going to be stuck transferring the overhead.