In this instance would you create four indexes key(a) key(b) key(a,b) key (b,a) ? Or is the decision based on the query response time ?
On 11 Oct 2011, at 13:40, Rik Wasmus <r...@grib.nl> wrote: >> Next question. If you have the two separate indexes and then do two >> queries, one for a and one for b. If you then get a list of unique id's >> of both, would it be faster to create an intersection yourself rather >> than have the server do the legwork? > > If you only have 2 unrelated indexes on a & b, it depends on the data, the > distribution of values, etc. No single answer here, test with your data and > you'll have the results. > > If you need it often, I'd go for the combined index & let MySQL do the work, > which is probably fastest. > -- > Rik Wasmus > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/mysql?unsub=neil.tompk...@googlemail.com > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org
