When the database contains a very large amound of attributes, the SQL query generated by eZContentObject::fillNodeListAttributes generates a very big "Using where; Using temporary; Using filesort" in MySQL which slows down the page generation.

The idea is to split this query into smaller ones which should be executed much faster.

On small sites, the difference might not be noticeable it might even slow the pages down a bit, but on sites with a lot of content (more than 100K attributes) this should make the difference.