Multiple indexes vs single index on multiple columns in postgresql : <p>I could not reach any conclusive answers reading some of the existing posts on this topic.</p>

<p>I have certain data at 100 locations the for past 10 years. The table has about 800 million rows. I need to primarily generate yearly statistics for each location. Some times I need to generate monthly variation statistics and hourly variation statistics as well. I'm wondering if I should generate two indexes - one for location and another for year or generate one index on both location and year. My primary key currently is a serial number (Probably I could use location and timestamp as the primary key). </p>

<p>Thanks.</p>
