Refer to the figure: Three Optimization Layers

A system processes database queries using Python, with no indexes, and SELECT * retrieving all 15 columns. Three independent optimisations target different layers:

Option A (Language Layer): Rewrite from Python to Go, reducing CPU overhead per query
Option B (Data Layer): Add a database index, reducing pages read by 98%
Option C (Query Layer): Change SELECT * to 3 specific columns, reducing data volume by 85%

If only one optimisation can be applied, which would have the largest impact on energy consumption, and what is the reasoning?

Question

Refer to the figure: Three Optimization Layers 
    
 A system processes database queries using Python, with no indexes, and SELECT * retrieving all 15 columns. Three independent optimisations target different layers: 
 
 Option A (Language Layer):  Rewrite from Python to Go, reducing CPU overhead per query 
 Option B (Data Layer):  Add a database index, reducing pages read by 98% 
 Option C (Query Layer):  Change SELECT * to 3 specific columns, reducing data volume by 85% 
 
 If only one optimisation can be applied, which would have the largest impact on energy consumption, and what is the reasoning?

Accepted Answer

Option B, because the index eliminates the dominant cost: reading thousands of irrelevant disk pages per query, which is the most energy-expensive operation in the pipeline

Answer

Option A, because language overhead is the largest contributor to energy consumption in any system

Answer

Option C, because reducing data volume affects every stage of query processing

Answer

All three options produce equal reductions because they each address one layer

Crowdly

Refer to the figure: Three Optimization Layers A system processes data...

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