A few hours ago I issued the following command in commonswiki_p mysql> select * from logging where log_namespace=6 and log_title='Estatuas_y_fuentes_de_La_Granja_de_San_Ildefonso_1.jpg' limit 10; Empty set (1 hour 5 min 33.53 sec)
Why does it take so long? There should be an index on it, which could be used to resolve the whole query as empty: > CREATE INDEX /*i*/page_time ON /*_*/logging (log_namespace, log_title, log_timestamp); If we explain the select > mysql> explain select * from logging where log_namespace=6 and > log_title='Estatuas_y_fuentes_de_La_Granja_de_San_Ildefonso_1.jpg' > limit 10; > +----+-------------+---------+------+---------------+-----------+---------+-------+----------+-------------+ > | id | select_type | table | type | possible_keys | key | > key_len | ref | rows | Extra | > +----+-------------+---------+------+---------------+-----------+---------+-------+----------+-------------+ > | 1 | SIMPLE | logging | ref | page_time | page_time | > 4 | const | 13607245 | Using where | > +----+-------------+---------+------+---------------+-----------+---------+-------+----------+-------------+ > 1 row in set (0.00 sec) it does show the index, but the key_len is only 4. It seems it is using page_time only for the log_namespace, and not for the log_title, so it needs to scan 13607245. Compare that with my local server, where that query provides a key_len of 261. Is the index set correctly? Why is mysql not taking log_title from the index into account? I first thought that perhaps the master wasn't using a full index, and that's what the toolserver replicated, but the index in the master looks complete: http://pastebin.com/vjyjZ7Y2 I also tried fetching the page_id from page using page_namespace and page_title, which is fast, and then searching logging using log_page (indexed by log_page_id_time), but page_id is missing from the view. _______________________________________________ Toolserver-l mailing list ([email protected]) https://lists.wikimedia.org/mailman/listinfo/toolserver-l Posting guidelines for this list: https://wiki.toolserver.org/view/Mailing_list_etiquette
