Your SQL Server workload and environment may not run with the performance you expect or require, and you'll need to troubleshoot the SQL Server. For a good troubleshooting approach, you need to have a basic understanding of the SQL Server architecture and internals, since SQL Server is a very complex software. There are four major components of the SQL Server architecture:
- SQLOS
- Storage engine
- Query processor
- Protocol layer
In the following image, you can see all these components and their relationship: