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CQL Set Addition
I'd like to know how users of Cassandra, YugaByte, Scylla, and other CQL-style databases understand the behavior of CQL sets. You can help!

The CQL documentation ( shows how to create a set using INSERT, and how to add elements to a set using UPDATE. Imagine that the following series of CQL statements are executed, possibly by distinct clients, in strict real-time order--that is, each request completes successfully before the next begins.

CREATE TABLE sets (id int PRIMARY KEY, value set<int>);

INSERT INTO sets (id, value) VALUES (0, {});

UPDATE sets SET value = value + {1} WHERE id = 0;

SELECT value FROM sets WHERE id = 0;

Every statement is executed at ConsistencyLevel ALL, and every statement completes successfully. Every statement is submitted exactly once, and no retries occur. An arbitrarily long delay precedes the final read. All nodes are running and the network is completely connected.
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Which of these values would you expect the final read to observe? *
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