This is one of the top slow queries in tenderil:
```
155 324 50 7,873 db2059 wikiuser wikidatawiki
SELECT /* ApiQueryPagePropNames::execute */ DISTINCT pp_propname FROM page_props ORDER BY pp_propname LIMIT 501 /* eca54e37324ba61f23cd87946fe72863 db2059 wikidatawiki 29s */
```
Query plan:
```
mysql:wikiadmin@db2052 [wikidatawiki]> EXPLAIN SELECT /* ApiQueryPagePropNames::execute */ DISTINCT pp_propname FROM `page_props` ORDER BY pp_propname LIMIT 501;
+------+-------------+------------+-------+---------------+------------------+---------+------+----------+-------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+-------------+------------+-------+---------------+------------------+---------+------+----------+-------------+
| 1 | SIMPLE | page_props | index | NULL | pp_propname_page | 66 | NULL | 59183780 | Using index |
+------+-------------+------------+-------+---------------+------------------+---------+------+----------+-------------+
1 row in set (0.00 sec)
```