Implicit conversion of Integer to VARCHAR - response (3) by dnoeth

Hi Nishant,
"group_amps" during an all-AMPs step usually means the optimizer assumes that less than 50% of the AMPs in the system will actually do some work, but the actual AMPs are not known before the query runs. E.g. the optimizer remembers which AMPs put some rows in spool and only those receive the next step.
 
Dieter