In a DB2 Explain Plan, what does TBSCAN GENROW
(line 5 below) mean?
SELECT STATEMENT ( Estimated Costs = 1.811E+03 [timerons] )
1 RETURN
2 NLJOIN
3 [O] TBSCAN
4 SORT
5 TBSCAN GENROW
6 [I] FETCH EKKO
7 IXSCAN EKKO~1 #key columns: 2
The IBM docs say GENROW
is
"A built-in function that generates a table of rows, using no input from tables, indexes, or operators"
What does that mean from a performance perspective?
Also, this is in an SAP system if that matters.