As we move towards a more digital-centric world, configuring server settings for performance in order to accommodate and effectively manage high volumes of data has become a pressing need. In this post, we will discuss how to optimize Microsoft Azure SQL server performance by configuring server settings. This topic is also part of the “DP-300 Administering Microsoft Azure SQL Solutions” exam.
Azure SQL Database Performance Levels
Azure SQL Database provides different performance levels, among which you can select based on the needs of your applications. Each performance level provides a certain amount of resources, which in turn gives a specific amount of Database Transaction Units (DTUs) or vCores. The three primary service tiers in SQL Database are:
- General Purpose / Standard: For most business workloads with balanced compute and storage
- Business Critical / Premium: For high transactional volume and fast storage
- Hyperscale: For large scale and rapidly expanding data
| Service Tier | Storage Size | IO Throughput | DTU Limit |
|---|---|---|---|
| General Purpose/Standard | From 5GB to 1TB | Medium | 3000 |
| Business Critical/Premium | From 5GB to 4TB | High | 4000 |
| Hyperscale | From 10GB to 100TB | Very High | No limit |
Server Configuration Parameters
To enhance the performance of Azure SQL database, several server parameters can be configured:
- Max Degree of Parallelism (MAXDOP): It sets the maximum number of processors to be used in a parallel plan execution. Range is 0-64. A value of 0 allows SQL Server to decide the maximum number of processors to use for parallel plan execution, while a specific value limits the number of processors for parallel plan execution.
- Cost Threshold for Parallelism: It sets the cost at which SQL Server will consider parallelizing queries. The default value is 5.
- Optimize for Ad Hoc Workloads: When enabled, the server will store a small compiled plan stub in the plan cache the first time a prepared statement or ad-hoc batch is executed.
To configure these server parameters, use the following SQL commands:
ALTER DATABASE SCOPED CONFIGURATION
SET MAXDOP = number_of_processors;
ALTER DATABASE SCOPED CONFIGURATION
SET COST_THRESHOLD_FOR_PARALLELISM = cost_value;
ALTER DATABASE SCOPED CONFIGURATION
SET OPTIMIZE_FOR_AD_HOC_WORKLOADS = ON | OFF;
Indexing
Indexes are crucial for query performance. Azure SQL Database includes automatic index tuning, which provides recommendations for indexes to add and remove. Of course, manual index tuning also can be performed for specific workload requirements.
You can use CREATE INDEX, ALTER INDEX, or DROP INDEX operations to create new indexes, modify/disable existing indexes, or delete unnecessary indexes respectively.
For example,
CREATE INDEX idx_column1_column2 ON your_table (column1, column2);
Conclusion
Although Azure SQL database offers many built-in tools and options specifically designed for performance tuning, it’s important to know the fundamentals like how to configure server settings and use indexes efficiently. Remember, optimizing these settings correctly is key to maximizing server performance. These server configuration techniques will not only enhance your day-to-day performance, but also prove useful in acing the “DP-300 Administering Microsoft Azure SQL Solutions” exam.
Practice Test
True or False: Performance tuning in Azure SQL Database is not necessary as it automatically adjusts to workload demands.
- True
- False
Answer: False
Explanation: Azure SQL Database performance tuning is necessary to maintain optimal performance. While Azure SQL Database provides intelligence tuning suggestions, the user should properly configure different parameters to suit the application’s needs.
Which of these server settings can be configured for optimal Azure SQL Database performance?
- A. DTU Purchasing model
- B. Azure AD authentication
- C. Read/write distribution
- D. User connections
Answer: A, C, D
Explanation: Server settings such as DTU purchasing model, read/write distribution, and user connections can be configured to improve Azure SQL database performance. Azure AD authentication is a security feature and does not necessarily affect performance.
True or False: Azure SQL Database always turns ON auto-tuning by default when creating a new SQL Database.
- True
- False
Answer: True
Explanation: Auto-tuning is a feature in Azure SQL Database which is turned on by default to manage performance tuning automatically.
What does the MAXDOP configuration do in Azure SQL Database?
- A. It sets the maximum degree of parallelism for SQL query execution.
- B. It sets the maximum semantic processing pool configuration.
- C. It restricts the usage of database processor time.
- D. It determines the maximum storage that a database can use.
Answer: A
Explanation: MAXDOP (Maximum Degree Of Parallelism) configuration sets the maximum number of processors that are used for the parallel plan execution of a SQL query in Azure SQL Database.
True or False: Azure SQL Database generates automatic tuning recommendations for worst-performing queries.
- True
- False
Answer: True
Explanation: Azure SQL Database automatic tuning provides recommendations based on the continuous monitoring of your database, focusing on identifying worst-performing queries.
What is a Database Transaction Unit (DTU) in the context of Azure SQL Database?
- A. It is a combination of CPU, memory, and data I/O.
- B. It is a parameter to limit user connections.
- C. It refers to the data storage limit.
- D. It is the unit for user-request processing.
Answer: A
Explanation: A Database Transaction Unit (DTU) represents a blended measure of CPU, memory, and data I/O and transaction log IO in a ratio determined by Microsoft’s OLTP benchmark workload.
True or False: The DTU-based purchasing model is a better choice for larger databases with predictable performance requirements.
- True
- False
Answer: True
Explanation: The DTU-based purchasing model is a better choice for larger databases with predictable performance requirements as it simplifies capacity management by allowing customers to choose pre-configured bundles of compute, memory, and storage resources.
Which tool is used to monitor performance in Azure SQL Database?
- A. SQL Server Profiler
- B. Azure Portal
- C. SQL Server Management Studio
- D. Azure Data Studio
Answer: B
Explanation: Azure Portal provides built-in performance monitoring and tuning tools for Azure SQL Database.
True or False: Azure SQL Database supports elastic pool for managing the performance of multiple databases.
- True
- False
Answer: True
Explanation: Azure SQL Database provides elastic pools to manage and scale multiple databases that have varying and unpredictable usage demands.
What is the purpose of Query Performance Insights in Azure SQL Database?
- A. To tune single-use simple queries
- B. To identify root causes for performance issues
- C. To limit the number of user connections for optimal performance
- D. To measure the data storage utilization
Answer: B
Explanation: Query Performance Insights provides a portal experience in Azure SQL Database for identifying the root causes of performance issues.
Interview Questions
What is the purpose of configuring server settings in Microsoft Azure SQL for performance?
Optimizing server settings in Azure SQL enhances the performance by adapting to workload needs, allows a seamless user experience, and ensures efficient resource utilization.
Name the two key configurable server settings available in Azure SQL Database?
The two key configurable server settings in Azure SQL Database are: DTUs (Database Transaction Units) and vCores (Virtual Cores).
What are Database Transaction Units (DTUs)?
DTUs represent a blended measure of CPU, memory, I/O (data and transaction log IOPS), and log write throughout for Azure SQL. A specific level of resources is dedicated to a database with a guaranteed amount of resources.
What is the importance of vCores in Azure SQL Database?
vCores represent virtual cores in Azure SQL Database. They allow users to choose the number of cores and memory by workload requirements, providing a high degree of control and management over scalability and cost.
How do you configure server-level firewall rules in Azure SQL Database?
Server-level firewall rules in Azure SQL Database can be configured using the Azure portal, Azure CLI, PowerShell, or the REST API.
What is the function of the ‘Max Degree of Parallelism’ server configuration setting in Azure SQL Database?
‘Max Degree of Parallelism’ sets the number of processors that are used for the execution of a query in a parallel plan. This can help increase performance for large, complex queries.
What is a performance tier in Azure SQL Database?
Performance tiers (also known as Service tiers) in Azure SQL Database are differentiated sets of resources and capabilities that allow customers to match the database performance capabilities to the application requirements.
What tool is used to monitor the performance of Azure SQL Database?
Azure SQL Database uses the Azure SQL Analytics tool available in the Azure portal to monitor performance.
What happens if you exceed your DTU limit on Azure SQL Database?
If you exceed your DTU limit on Azure SQL Database, you may experience a slowdown in operations as your database will be throttled until enough resources become available.
How do you handle surges in activity to reduce DTU consumption in Azure SQL Database?
Azure SQL Database allows you to scale out with read replicas or scale up to higher performance tiers to handle surges in activity and manage DTU consumption.
What is the role of Azure’s Elastic Pool in managing resources?
Azure’s Elastic Pool allows you to manage and allocate resources flexibly across multiple databases, helping to optimize computing resource utilization and cost-efficiency.
How can you minimize latency for read-intensive workloads in Azure SQL Database?
You can minimize latency for read-intensive workloads in Azure SQL Database by creating read replicas which distribute read workloads across multiple databases.
What is the ‘auto-pause delay’ in the Azure SQL Database?
‘Auto-pause delay’ is a configuration in Azure SQL Database which specifies the amount of time of inactivity after which the database is automatically paused to save costs.
What is the function of the ‘tempdb’ database in Azure SQL Database?
The ‘tempdb’ database in Azure SQL Database is a system database that is used to store temporary tables and other temporary database objects. It is shared across all databases in an Azure SQL Database server.
What are ‘Elastic Jobs’ in Azure SQL Database?
‘Elastic Jobs’ in Azure SQL Database are intended to perform administrative tasks on a group of databases, such as schema changes, credentials management, performance data collection, etc.
extutorials.com