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What can be said about the query plan's optimality? MVCC There is a table CREATE TABLE orders ( id BIGSERIAL PRIMARY KEY, status TEXT, updated_at TIMESTAMP ); and a query running every second UPDATE orders SET status = 'processed', updated_at = now() WHERE id = 1; After a few days, you notice: • the table size has grown significantly • the query SELECT * FROM orders WHERE id = 1 runs slower Questions for the candidate: 1. Why does the table grow even though the row is always the same? 2. What role does MVCC play in this situation? 3. What should solve this problem?

Why must the eigenvalues be non-zero for the inverse matrix to exist?