Database performance refers to how efficiently a database system processes queries and transactions. It is measured by factors such as response time, throughput, and resource utilization. High performance means that the database can handle many requests quickly, while low performance can lead to delays and bottlenecks. Improving database performance often involves optimizing queries, indexing data, and ensuring proper hardware resources. Tools and techniques like database tuning and caching can help enhance performance. Regular monitoring is essential to identify issues and maintain optimal operation, ensuring that users have quick access to the information they need.