The Query Store is a powerful feature in SQL Server that helps monitor and optimize query performance. However, when dealing with temporary objects, it’s important to consider their impact on query performance and how to effectively manage them in conjunction with the Query Store. In this blog post, we will discuss some best practices to follow when working with temporary objects and optimizing query performance using the Query Store.

Temporary Objects and Query Performance

Temporary objects, such as temporary tables and table variables, are frequently used in SQL Server to store intermediate results during query execution. While they can be useful, they can also introduce performance issues if not managed properly.

One common problem is the creation and destruction of temporary objects, which can lead to wasted resources and increased overhead. When the Query Store is enabled, it automatically captures and stores execution plans for queries, including those involving temporary objects. This means that the performance impact of temporary objects will be captured and potentially affect the overall query performance analysis.

Best Practices for Managing Temporary Objects

To effectively manage temporary objects and optimize query performance with the Query Store, consider following these best practices:

1. Minimize the use of temporary objects: Whenever possible, try to find alternative solutions that avoid the need for temporary objects. For example, you can use derived tables, common table expressions (CTEs), or indexed views to store intermediate results.

2. Properly index temporary objects: If you must use temporary tables, ensure that you have appropriate indexes in place to improve query performance. Analyzing and understanding the query execution plans captured by the Query Store can help identify the right indexes to create.

3. Limit the scope and lifetime of temporary objects: Consider the scope and lifetime of your temporary objects. Use table variables instead of temporary tables when the data volume is small, and the object can be easily created and destroyed within the same procedure or batch.

4. Avoid excessive object creation and destruction: Reusing temporary objects can significantly improve performance. Instead of constantly creating and dropping temporary tables, consider creating them once and using truncate or delete statements to remove the data in subsequent runs.

Query Performance Analysis with the Query Store

The Query Store provides valuable insights into query performance. To effectively analyze and optimize query performance, consider the following practices:

1. Monitor and review query performance: Regularly review the Query Store reports and metrics to identify queries with performance issues. Look for queries involving temporary objects and analyze their execution plans to understand their impact on performance.

2. Leverage the Query Store performance tools: Take advantage of the performance tools provided by the Query Store, such as the Query Store GUI, system views, and dynamic management views (DMVs). These tools allow you to analyze query plans, resource consumption, and execution statistics.

3. Use query tuning techniques: Apply query tuning techniques, such as rewriting queries, adding or removing indexes, or updating statistics, to address performance issues identified through Query Store analysis. Pay special attention to queries involving temporary objects and test different variations to find the optimal solution.

Conclusion

Managing temporary objects and optimizing query performance with the Query Store requires careful consideration and analysis. By following these best practices, you can minimize the impact of temporary objects on query performance and leverage the Query Store’s capabilities to identify and resolve performance issues effectively.

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