We had a huge spike on commonswiki after running the train of 1.33.0-wmf.8
The query is the following:
SELECT /* ApiPageSet::initFromPageIds */ page_namespace, page_title, page_id, page_content_model, page_lang, page_len, page_is_redirect, page_latest FROM `page` WHERE page_id IN ('-1', '-2') /* 8ac75033ec8e7474569731213f57d591 db1084 commonswiki 32s */The explain is for:
+------+-------------+-------+------+---------------+------+---------+------+----------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +------+-------------+-------+------+---------------+------+---------+------+----------+-------------+ | 1 | SIMPLE | page | ALL | PRIMARY | NULL | NULL | NULL | 67236817 | Using where | +------+-------------+-------+------+---------------+------+---------+------+----------+-------------+