In T345664 we are considering allowing client preferences to be usable by logged in users. While one motivation for this is to allow different experiences on different devices (e.g. laptop, desktop, tablet) another concern we have is impact on the database which we'll explore as part of this task.
The motivation for this is we expect that at least 15% of users will use a font size preference and a significant amount of users would likely make use of a dark mode (possibly > 50%) [1] and we would want light mode to be the default experience.
Given we have two skins for mobile and desktop on two very different mediums, we think it is essential that preferences do not apply across skins, so for each of these preferences we would need 2 preferences.
# Question to answer
Would a situation where we have 15% of users have 2 preferences stored for font size, and 50%+ users have 2 preferences stored for dark mode be problematic from a DBA POV? If so, how should we adjust our implementation?
[1] https://marketsplash.com/dark-mode-usage-statistics/