Viewing Special:Recentchanges as a logged-in user results in a huge amount of database queries. In particular, the following three queries are run for every row:
SELECT /* Title::loadRestrictions */ * FROM page_restrictions WHERE pr_page = '142'
SELECT /* Title::loadRestrictionsFromRow */ page_restrictions FROM page WHERE page_id = '142' LIMIT 1
SELECT /* Title::getLatestRevID */ page_latest FROM page WHERE page_id = '142' LIMIT 1
It should be easy to merge the first two queries. Also, the results aren't cached, which means that 5 changes to page_id 142 results in the aforementioned query block being run 5 times, each time with the exact same results.