Select Star Over Fetch (ARCH6066)

Key ruby.orm.select-star-over-fetch · Severity info · Category orm

Fetching the full entity/all columns when only a few fields are used downstream needlessly inflates row width and serialization cost. A projection (select/pluck) is suggested.

Incorrect

users = User.where(active: true)
names = users.map(&:name)  # all columns fetched, only name used

Correct

names = User.where(active: true).select(:name).map(&:name)

Fix

Project only the needed fields with select/pluck instead of fetching all columns.