Systems
Dirty Reads, Explained
A dirty read returns an uncommitted value from another transaction. If that transaction rolls back, the reader observed a value that was never part of committed database state.
Aug 8, 2026·5 min read
A dirty read returns an uncommitted value from another transaction. If that transaction rolls back, the reader observed a value that was never part of committed database state.
A transaction reads the same row twice and gets two different committed values. The isolation level determines whether both reads use the same database state.
A transaction repeats a search and finds an additional matching row. The existing rows did not change, but another transaction committed a new row that satisfies the same query.
A green lock only proves one network hop is protected. End-to-end encryption moves the trust boundary so the server can carry a message without being able to read it.