On Fri, Feb 27, 2009 at 2:29 AM, Tim Starling tstarling@wikimedia.org wrote:
On thistle with DB=dewiki:
mysql> explain select * from recentchanges left join tag_summary on ts_rc_id=rc_id order by rc_timestamp desc limit 50\G
*************************** 1. row *************************** table: recentchanges type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 1179921 Extra: Using temporary; Using filesort *************************** 2. row *************************** table: tag_summary type: ALL possible_keys: ts_rc_id key: NULL key_len: NULL ref: NULL rows: 4 Extra: 2 rows in set (0.00 sec)
Almost two months later, but now that I have access to the toolsever DB, here's some output from zedler on dewiki:
mysql> SELECT VERSION(); +-----------+ | VERSION() | +-----------+ | 5.1.33 | +-----------+ 1 row in set (0.00 sec)
mysql> explain select * from recentchanges left join tag_summary on ts_rc_id=rc_id order by rc_timestamp desc limit 50\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: recentchanges type: index possible_keys: NULL key: rc_timestamp key_len: 16 ref: NULL rows: 50 Extra: *************************** 2. row *************************** id: 1 select_type: SIMPLE table: tag_summary type: ref possible_keys: ts_rc_id key: ts_rc_id key_len: 5 ref: dewiki.recentchanges.rc_id rows: 1 Extra: 2 rows in set (0.00 sec)
So "MySQL 5.1" is a valid answer. (EXPLAIN even understands LIMIT now, yay!)