How DB2 Gets Your Data

1. Buffer manager read your tables/index off disk and places the data in its buffers
2. Buffer manager passes pages (4k) to the Data manager
3. Data manager process stage 1 predicates (indexable)
-where clauses like: col1 = value ,col1 between values ,col1 like A%
4. Data manager passes data to program if where clause ONLY contains stage 1 predicates, otherwise it passes a row at a time to RDS (Relational Data System)
5. RDS process all stage 2 predicates (not indexable)
-build in functions: MAX, MIN, SUM
-any expressions: col1 + col2
-where clauses like: col1 like %A
6. RDS passes data to program