On enwiki:
+------------------+----------------------------+-----------+ | table_name | index_name | rows_read | +------------------+----------------------------+-----------+ | article_feedback | PRIMARY | NULL | | article_feedback | article_feedback_timestamp | NULL | | article_feedback | aa_page_id | NULL | | article_feedback | aa_page_user_token | NULL | +------------------+----------------------------+-----------+ 4 rows in set (0.25 sec)
NULL rows_read indicates the indexes havn't been used. Stats collection has been running here for over a week. Same results on S1 master and several slaves.
Indexes outweigh data on article_feedback quite a bit, taking up space and increasing write load:
+---------------------------------------+--------+-------+--------+ | CONCAT(table_schema, '.', table_name) | rows | DATA | idx | +---------------------------------------+--------+-------+--------+ | enwiki.article_feedback | 69.00M | 7.13G | 26.04G | +---------------------------------------+--------+-------+--------+
Surprising; now I'm suspicious of the stats... Are these indexes really likely to be simply unused?
Is there any infrequent maintenance or reporting job that requires them?
Version: wmf-deployment
Severity: minor