Where Predictability Shows Up 50 1=81()≈100 40 35 (s)≈25+10s 30 20 Plan 1 15 Plan 2 81(c1) 10 100 25 0 0% 20% 40% 60%80%100% 10 Query Selectivity Figure l: Execution Costs for Two Hypothetical PlansWhere Predictability Shows Up 10 25 ( ) 100 1 ( ) ( ) 25 10 ( ) 100 2 2 1 2 1 1 1 1 2 2 1 1 − = = = = =  + =  − − c s g c s g c c c g s s c g s s