Issue link: https://resources.awscloud.com/i/1496544
update after a major change, which means that query plans and overall performance might take a while to return to desired lev‐ els. Distributed optimization In fast-changing application environments, the developers understand the database queries better than the DBA. If they take on query testing and optimization, they can achieve good performance faster than the DBA can, freeing the DBA to do long-term optimizations and planning. Knowing the importance of performance, cloud vendors have inser‐ ted traces and exposed a large number of statistics to users. AWS's RDS Performance Insights, for instance, lets you pull up historical data on a dashboard and view charts showing the load placed by particular operations, users, or SQL statements on the database. You can consult the dashboards to answer simple questions such as "When are my hosts overloaded?" or more complex ones such as "What is making this query produce suboptimal performance?" Azure offers both performance monitoring and automatic tuning. Third-party vendors also produce tools for monitoring and perfor‐ mance in the cloud. Adapting to Differences in the Cloud Finally, the vendor themselves will offer new services, new VM options, new hardware (such as SSDs), and other changes that can offer you big benefits. Always be aware of what the vendor can do for you, so that you can offload work onto its well-tested and stand‐ ardized processes. As you do so, update your documented opera‐ tional procedures. Finally, you can report abnormal events to the vendor's customer support, indicating the urgency of the event. Conclusion A migration to the cloud is a long-term process. Start small, because you will find you have a lot to learn along the way. Keep a journal and honestly record all the mistakes and problems encountered. Don't be embarrassed if legacy systems harbor poor practices or out‐ right bugs that turn up during the migration—that will happen in virtually every organization. Documenting the problems is the best thing you can do for your company. Conclusion | 37