Why does it take so long to rename a column in mysql?

Question

I have a 12 GB table full of pictures, I\'m trying to rename the blob column that holds the data, and it is taking forever. Can someone give me a blow by blow account of why

Answer 1

Yes mysql does a temporary copy of the table. I don't think there's an easy way around that. You should really think about to store the pictures on the filesystem and only store paths in mysql. That's the only way to fasten it up, I guess.