Regardless of the setting for number of results per page, I'm getting all results returned. This becomes a problem with categories which have hundreds or thousands of results, and the page sometimes never loads.
You can see here, 1 results per page selected but 21 results returned:
I have configured the defaults in the admin console, and I've also tried to configure it in local.xml but the settings don't seem to be honoured, I'm always getting all results returned.
It also doesn't matter whether I use Magento's built in database search, Solr, or ElasticSearch, the same problem exits which suggests to me that something before it gets as far as asking for results is failing to paginate.
The same problem happens on the default theme.