What “Clustered Index Scan (Clustered)” means on SQL Server execution plan?

Question

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\'\".

On the

Answer 1

If you hover over the step in the query plan, SSMS displays a description of what the step does. That will give you a baseline understanding of "Clustered Index Scan (Clustered)" and all other steps involved.