Social & feeds
Social news feed - fan-out on write or on read
Fan-out on write against fan-out on read, and when each loses.
What this board gets wrong on purpose
The tension
Fan-out on write is drawn as the default and it breaks on the celebrity: one publish by an account with ten million followers becomes ten million writes, and while the workers chew through that single post every ordinary post is stuck behind it. The threshold on the fork is a hardcoded number nobody can defend, and the board does not say what happens to an account that crosses it between one post and the next.
The rest of this board
Available on Tier Slate
This page publishes the question. The answer — an 8-step narrated walkthrough — is the board itself, and it opens in Tierslate.
- 8walkthrough steps
More boards
Timelines, follows, fan-out - the read-heavy classics.