Where Predictability Shows Up 50 40 C1=81(S)≈100s 35 g2(S)≈25+10 30 20 Plan 1 15 Plan 2 0 0% 20% 40% 60%80%100% Query Selectivity Figure l: Execution Costs for Two Hypothetical PlansWhere Predictability Shows Up c g s s c g s s ( ) 25 10 ( ) 100 2 2 1 1 =  + = 