Why is the Repeatable Read isolation level needed in this context and is it necessary?

The Repeatable Read isolation level guarantees that within a single transaction, all repeated reads of the same data will return the same result, even if other transactions concurrently modify that data. This prevents the phenomenon of non-repeatable reads.

In contexts where data consistency is crucial during long transactions or complex business operations, this isolation level helps avoid errors related to data changes during transaction execution.

However, Repeatable Read can reduce concurrency and increase locking, which impacts performance. Therefore, its use is justified if:

• Strict data consistency within a transaction is required.
• There is a risk of logical errors due to data changes between reads.

If an application can operate with less strict consistency or uses other control mechanisms, this level may be excessive.