CockroachDB 23.2 introduces support for both SERIALIZABLE and READ COMMITTED isolation levels, providing guidance for users to select the appropriate transaction isolation level for their applications. SERIALIZABLE, which prevents all isolation anomalies, is the default and highest isolation level, but it results in more transaction retry errors due to its conservative detection of potential interference between transactions. READ COMMITTED, a weaker isolation level, is commonly used in other databases because it minimizes blocking and interference, offering more predictable performance while requiring careful use of explicit locks to prevent data bugs. The choice between these isolation levels significantly impacts application development: lower isolation levels necessitate explicit locking, whereas higher isolation levels may require retry loops in the application code to handle transaction retry errors. The article emphasizes the importance of understanding these practical implications over the specific data anomalies prevented or allowed by each isolation level.