Using MW 1.23.13, PHP 5.6.20-0 and PostgreSQL 9.4.6 you get an error when trying to access Special:Protected_pages
A database query error has occurred. This may indicate a bug in the software.
Query:
SELECT pr_id,page_namespace,page_title,page_len,pr_type,pr_level,pr_expiry,pr_cascade, log_timestamp,log_user,log_comment,log_deleted FROM "page","page_restrictions" LEFT JOIN "log_search" ON (ls_field = 'pr_id' AND (ls_value = pr_id)) LEFT JOIN "logging" ON ((ls_log_id = log_id)) WHERE (pr_expiry > '2016-05-13 09:54:51 GMT'OR pr_expiry IS NULL) AND (page_id=pr_page) AND (pr_type='edit') ORDER BY pr_id LIMIT 51Function: IndexPager::buildQueryInfo (ProtectedPagesPager)
Error: 42883 ERROR: operator does not exist: text = integer LINE 1: ..."log_search" ON (ls_field = 'pr_id' AND (ls_value = pr_id)) ...
^ HINT: No operator matches the given name and argument type(s). You might need to add explicit type casts.
Reason is, ls_field and ls_value are text but pr_id is integer.
Error lies in SpecialProtectedpages.php around line 545. Tried to fix this myself, but my php knowledge isn't good enough.