When two or more transactions occur at the same time, the isolation level defines the degree at which a transaction is isolated from the resource or data modifications made by other transactions. There are four types of isolation levels; to change the isolation level, you need to set the tx_isolation variable which is dynamic and has session level scope.
Isolation levels
How to do it...
To change this level, execute SET @@transaction_isolation = 'READ-COMMITTED';.
Read uncommitted
The current transaction can read data written by another uncommitted transaction...