title: Left Join performance on Spanner
body: <p>We encountered with a disturbing issue. Seems that when we are using left join on the Google Spanner it suffers from bad performance.</p>
  
  <p>The left join operator cause to full scan on the right tables rows from some reason...</p>
  
  <p>Anyone else encountered with this?
  Of course that when we're removing the left join operator and just using inner join the performance is good...</p>
  
  <p>Execution Plan:</p>
  
  <p><a href="https://i.stack.imgur.com/YPAqB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/YPAqB.png" alt="enter image description here"></a></p>