When publishing an image with a rather big ezcontentobject_attribute table the following query becomes unbearably slow:

SELECT id, version FROM   ezcontentobject_attribute WHERE  data_type_string = 'ezimage' and data_text like '%url="var/siteaccess/storage/images/path-to-image.jpg"%'

This query is executed as part of the removal of the oldest version when an object has hit the DefaultVersionHistoryLimit in content.ini.

Current size of ezcontentobject_attribute:

mysql> select count(*) from ezcontentobject_attribute;
+----------+
| count(*) |
+----------+
|  1272091 | 
+----------+

Steps to reproduce

1. Publish a new image object.
2. Re-publish it 5/6 times (or whatever DefaultVersionHistoryLimit is set to).
3. Upload a new image to the same image object and publish it.
4. Watch the database cry while executing the slow like query.