Martijn Tonies wrote: > > Hi, > > > You are not using any indicies, because there aren't any that could be > > used in this query. > > Try adding an index on (status,deleted) > > I wonder: how many possible different values would such an index > return?
mysql> select distinct status, deleted from urlword; +--------+---------+ | status | deleted | +--------+---------+ | 200 | 0 | | 503 | 0 | | 302 | 0 | | 0 | 1 | | 200 | 1 | | 504 | 0 | | 301 | 0 | | 0 | 0 | | 204 | 0 | | 420 | 0 | | 1 | 0 | | 303 | 0 | | 470 | 0 | +--------+---------+ 13 rows in set (6 min 55.94 sec) mysql> select distinct status, deleted, origin from urlword; ... 23 rows in set (7 min 9.90 sec) > If this is a (very) low value, won't the index make things > slower (if it's being used) compared to a full table scan? I guess these values are very low for a table with 46 milion records, so I understand it is better not to use such indicies, right? > > With regards, > > Martijn Tonies > Database Workbench - developer tool for InterBase, Firebird, MySQL & MS SQL > Server. > Upscene Productions > http://www.upscene.com > Thanks, Martijn, Janusz -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
