How do isolation levels affect concurrency?

What are isolation levels in databases?

Isolation levels define how transaction integrity is visible to other transactions. They control the visibility of changes made by one transaction to others.

How do these levels affect concurrency?

Different isolation levels can either enhance or restrict concurrency. For example, 'Read Uncommitted' allows high concurrency but risks dirty reads, while 'Serializable' ensures data integrity but can lead to more locking and reduced concurrency.

Can you give examples of each isolation level?

Sure! The main isolation levels are: 1. Read Uncommitted 2. Read Committed 3. Repeatable Read 4. Serializable. Each has its trade-offs between consistency and concurrency.

Which isolation level is best for high-performance applications?

For high-performance applications, 'Read Committed' is often a good balance, providing reasonable consistency while allowing for better concurrency.