Chapter 8 Quality attributes and sizing of the dXp • Appropriate authorization and access controls should be defined for the log files. • All sensitive operations such as creating a user, deleting an account, or updating an account should be persisted in the audit table. The audit table should store the transaction ID, user ID, timestamp, old value, new value, and the operation type (create, update, delete). Performance Requirements A system’s performance is measured by metrics such as response times, page load time, etc. Following are the main performance requirements. We discuss DXP performance in detail in Chapter 9. • The response time of web pages should be within 2 seconds across all geographies and all access channels during average load. In order to fulfill strict SLAs across all geographies, we may need to use content delivery network (CDN) and geo-centric applications. • If the system takes more than 5 seconds for any transaction, the system should display an informative message or graphical icon to the end user. • The system should respond within accepted SLAs even during peak traffic and during maximum concurrent transactions. • The throughput for the web server and application server should be able to support maximum transactions and page views. Infrastructure Sizing of DXP A properly sized infrastructure is the most essential element for achieving optimum scalability and availability for the platform. This section looks at the key factors that can be considered for infrastructure sizing of a DXP. Note the following sizing calculation is for on-premise deployment. 222