Slow INSERT into InnoDB table with random PRIMARY KEY column's value

Question

For my website I use the PHP API for Flickr ( http://www.flickr.com/services/api/ ). This API provides several useful methods to get photos around particular GPS positions.<

Answer 1

InnoDB does not support hash keys, only Btree.

MyISAM is infamous for being unreliable.
I think your problem is that you use the MD5 value for the primary key.

The primary key is included in every secondary key. And the PK is forced to be a unique key.

Set an integer autoincrement primary key and set your MD5 value as a normal index.
It does not even need to be unique, because that's a huge part of what's slowing you down.

After this your inserts should run much faster.