title: What "Clustered Index Scan (Clustered)" means on SQL Server execution plan?
body: <p>I have a query that fails to execute with "Could not allocate a new page for database 'TEMPDB' because of insufficient disk space in filegroup 'DEFAULT'". </p>
  
  <p>On the way of trouble shooting I am examining the execution plan. There are two costly steps labeled "Clustered Index Scan (Clustered)". I have a hard time find out what this means? </p>
  
  <p>I would appreciate any explanations to "Clustered Index Scan (Clustered)" or suggestions on where to find the related document?</p>