[erik_seaberg]

A compare-and-set request. E.g., I can read version 3 of a row, and write version 4 if the current version is still 3, so that if someone else writes version 4 I don't clobber whatever they just did.

[gigatexal]

That’s a really succinct definition. I like it. Thank you.

[manigandham]

To be clear, "lightweight transactions" are a Cassandra specific term, nobody else uses that. Compare-and-set, atomic updates, or just transactions are the normal terms.