title: Cloud spanner: select count * takes over a minute
body: <p>I created a test table in cloud spanner and populated it with 120 million rows. i have created a composite primary key for the table.</p>
  
  <p>when i run a simple "select count(*) from " query, it takes approximately a minute for cloud spanner web UI to return results.</p>
  
  <p>Is anyone else facing similar problem?</p>