I had an opportunity to do some tuning on postgresql and was pleasantly surprised at how smoothly it went.

The first thing I did was try to run an “explain” on the query under discussion.  (Explain is a tabular or graphical view of the detailed steps the database uses to execute your query.  By knowing what path it will take and what tables/indexes it will look at, you can tune your query appropriately.) Knowing this works differently in different databases, I looked up what to do.  Here are the steps:

Mas:

http://www.selikoff.net/blog/2008/12/13/postgresql-explain/