A web application retrieves product data from a database and then sorts the results before displaying them. Currently, the database returns all 50,000 products (no index, full table scan), and the application sorts them using a method where doubling the input quadruples the work. Two changes are proposed:

Change A: Switch to a sorting method where doubling the input only doubles the work
Change B: Add a database index so only the 200 matching products are returned

Which change addresses the larger source of wasted energy?

Question

A web application retrieves product data from a database and then sorts the results before displaying them. Currently, the database returns all 50,000 products (no index, full table scan), and the application sorts them using a method where doubling the input quadruples the work. Two changes are proposed: 
 
 Change A: Switch to a sorting method where doubling the input only doubles the work 
 Change B: Add a database index so only the 200 matching products are returned 
 
 Which change addresses the larger source of wasted energy?

Accepted Answer

Change B, because it eliminates the unnecessary retrieval and processing of 49,800 irrelevant rows at the source

Answer

Both changes address the same bottleneck

Answer

Change A, because sorting is the most computationally expensive operation

Answer

Neither change is effective because network transfer dominates the energy cost

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A web application retrieves product data from a database and then sorts the resu...

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