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What are the transaction isolation levels supported by MariaDB server?
MariaDB supports the following isolation levels:
- READ UNCOMMITTED.
- READ COMMITTED.
- REPEATABLE READ.
- SERIALIZABLE.
Which ensure the isolation of the transaction?
Read Committed – This isolation level guarantees that any data read is committed at the moment it is read. Thus it does not allows dirty read. The transaction holds a read or write lock on the current row, and thus prevent other transactions from reading, updating or deleting it.
How to set isolation level in MariaDB transaction?
For more information about MariaDB isolation levels see SET TRANSACTION. In MariaDB, the locks acquired by a read do not depend on the isolation level (with one exception noted below). As a general rule: Plain SELECTs are not locking, they acquire snapshots instead. To force a read to acquire a shared lock, use SELECT LOCK IN SHARED MODE .
How is transaction isolation used to prevent inconsistency?
Isolation can prevent data inconsistency caused by cross execution when multiple transactions are executed concurrently. Transaction isolation is divided into different levels, including read uncommitted, read committed, repeatable read and serializable. Persistence means that the modification of data is permanent after the transaction is executed;
Is it possible to change the isolation level?
It is not possible to change the isolation level in the middle of a transaction. SNAPSHOT isolation level is not supported. Instead, you can use START TRANSACTION WITH CONSISTENT SNAPSHOT to acquire a snapshot at the beginning of the transaction. This is compatible with all isolation levels.
How does MariaDB support constraints in SQL Server?
MariaDB supports the following constraints: In some databases, constraints can temporarily be violated during a transaction, and their enforcement can be deferred to the commit time. SQL Server does not support this, and always validates data against constraints at the end of each statement.