How to make sure there is no race condition in MySQL database when incrementing a field?

Question

How to prevent a race condition in MySQL database when two connections want to update the same record?

For example, connection 1 wants to increase \"tries\" counter.

Answer 1

Use a single statement instead of two. A single UPDATE statement that performs both the read and the write will be atomic and won't conflict with another simultaneous update.

UPDATE table SET tries = tries + 1 WHERE ...

Or you can use transactions to make the two operations atomic.

BEGIN
SELECT ...
UPDATE ...
COMMIT

Or, more primitively, lock the table while you're reading/writing to it.

LOCK TABLES table WRITE
SELECT ...
UPDATE ...
UNLOCK TABLES