8

10

1

2

The extra columns cause the query to run slower because the database must sort more data

The database creates an index on all 20 columns, which increases write energy

The database must perform additional joins to retrieve the extra columns from related tables

All 20 columns are read from disk and transferred through memory for every matching row, even though 17 columns are discarded by the application

Disk I/O overhead from loading the interpreter into memory

Network overhead from communicating between the interpreter and the operating system

Interpreter dispatch overhead, where each application instruction requires many processor instructions to execute

Memory allocation overhead from creating temporary objects

The index compresses the table data so fewer pages are needed overall

The index reorganises the table on disk so that students in the same major are stored on consecutive pages

The index caches frequently accessed rows in memory so disk reads are avoided

The index stores a sorted copy of the major column with pointers to the corresponding rows, allowing the database to navigate directly to matching entries

The sorted order means each comparison reveals which half contains the target, making the other half irrelevant

The data is stored in contiguous memory, allowing the processor to prefetch adjacent records

The dataset fits entirely in the processor’s cache, eliminating memory access delays

The records are stored with pointers that connect each record to the next in sequence

Increasing fossil fuel consumption

Eliminating electricity distribution systems

Replacing all traditional power plants

Identifying and reducing energy wastage

Through household solar panels

Through small community microgrids

Through decentralized renewable sources

Through large centralized power facilities

To support the integration of renewable energy and digital energy management

To reduce internet traffic in cities

To reduce the number of power plants

To eliminate electricity storage technologies

55%

85%

70%

40%

To increase energy prices globally

To make energy production and consumption more efficient

To replace renewable energy with fossil fuels