> I suspect it would not be used as often as the primary key index

That doesn't matter because it's the creation of the index entry that matters, not how often it's used for lookup. The lookup cost is the same anyways.

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matthew16550 a day ago | parent [-]

The page I linked shows uses after creation where the cost can be different.

	▲	crazygringo 11 hours ago \| parent [-]
		Making the assumption: > Since workloads commonly are interested in recently inserted rows That's only true for very specific types of applications. There's nothing general about that. Plenty of applications grab rows from all time, and there's nothing special about the most recent ones. The most recent might also be the least popular rows, since few things reference them.