You need to rename a column that a live, heavily-used endpoint reads and writes. Zero downtime. How?
Answer it out loud before you open anything. The value of the flags below is in comparing them to what you actually said.
The situation behind the question
A rolling deploy means old and new application versions run simultaneously for several minutes. The table has tens of millions of rows.
What it is really testing
Whether the candidate internalises that during a rolling deploy two application versions share one database, so every migration must be compatible with the version before it and the version after it.