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mysqlisolation-levellocks

MySQL - Does the READ UNCOMMITTED isolation level use locks?

So I am trying to understand more about the isolation levels and I read that the READ UNCOMMITTED isolation level allows dirty readings which may lead to non-consistent readings. I also read that the

SELECT statements are performed in a nonlocking fashion

So my question is, does this type of isolation uses locks for other statements? For example, if I use the INSERT INTO statement does it acquire locks?

Solution

  • Yes. Locks are still needed to ensure data transactions are atomic.

    Also locks ensure that elements like auto_increments values only exist once.