Not sure if we talk of the same thing? When I say transaction I mean a number of queries between START TRANSACTION and COMMIT (or ROLLBACK) SQL command, and mys

Not sure if we talk of the same thing? When I say transaction I mean a number of queries between START TRANSACTION and COMMIT (or ROLLBACK) SQL command, and mysql will lock automatically all tables inside that block. If you use SELECT inside the transaction innoDB will work on a data snapshot to insure the data consistency. (btw. thanks for the link I'll read it later)