Sampling implementation - response (1) by dnoeth

No, it's not actually doing a Full Table Scan, only some "random" blocks are read.
But the speed of execution is dependent on the number of AMPs in the system, more AMPs mean slower execution.
On a system wtih a few hundred AMPs it will run for a few seconds even if the table is small (and this speed hardly changes for larger tables).
 
If you only want to see some rows, but don't need a statsitical sample, better use TOP syntax.
 
Dieter