What is your experience with the REPEATABLE_READ transaction isolation level in databases?

The REPEATABLE_READ transaction isolation level guarantees that within a single transaction, all repeated reads of the same data will return the same results, even if other transactions concurrently modify that data. This prevents the non-repeatable read problem, where data changes between two reads within the same transaction.

In practice, I used REPEATABLE_READ when it was necessary to ensure data consistency during complex read and update operations, such as processing orders or financial transactions. In Java, using JDBC or ORM (e.g., Hibernate), this isolation level can be set through connection methods or session configuration.

Example of setting the isolation level in JDBC:

connection.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
connection.setAutoCommit(false);
// Perform operations within the transaction
connection.commit();

It is important to remember that REPEATABLE_READ can reduce concurrency and increase the likelihood of locking, so it should be used when data integrity during repeated reads is crucial.