On Wed, Aug 3, 2011 at 3:27 PM, Li Jin <ljin@xxxxxxxxxxxxxxx> wrote: > Robert， > I've built an index on this expression firstname || ' ' || > substring(lastname,1,1). I believe this is the best index for this > particular query. Correct me if I am wrong. Maybe, maybe not. Difficult to tell from a distance. I would have an index on (firstname, lastname). You could try that and look at the plan for the other query. That's the only ultimate test which will give you hard facts. Kind regards robert -- remember.guy do |as, often| as.you_can - without end http://blog.rubybestpractices.com/ -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
