Parameter Sensitive Plan optimization - SQL Server 2022

Parameter sensitivity is a common challenge in SQL Server query optimization, where a single query can have multiple execution plans depending on the specific parameter values used. In SQL Server 2022, there are several improvements to the Parameter Sensitive Plan optimization feature that help to address this issue. Here are some of the key improvements and examples:

Batch Mode on Rowstore: SQL Server 2022 introduces the ability to execute queries in batch mode on rowstore data, which can help to improve performance for parameter sensitive queries. Batch mode processing is a high-performance data processing mode that can take advantage of vectorized operations and SIMD instructions, which can result in significant performance improvements.

For example, consider a query that retrieves all orders for a specific customer:

SELECT *

FROM Sales.Orders

WHERE CustomerID = @CustomerID

With batch mode on rowstore, SQL Server 2022 can use vectorized operations to process the query more efficiently, resulting in faster execution times.

Adaptive Memory Grant Feedback: In SQL Server 2022, the Adaptive Memory Grant Feedback feature has been improved to better handle parameter sensitivity. This feature dynamically adjusts the amount of memory allocated to a query based on its actual memory requirements. With the improvements in SQL Server 2022, this feature can now adjust memory grants more quickly for parameter sensitive queries, which can help to improve performance.

For example, consider a query that retrieves all orders for a specific date range:

SELECT *
FROM Sales.Orders
WHERE OrderDate BETWEEN @StartDate AND @EndDate

With Adaptive Memory Grant Feedback in SQL Server 2022, the amount of memory allocated to the query can be adjusted based on the specific date range being queried, resulting in more efficient memory usage and improved performance.

Improved Parameter Embedding: SQL Server 2022 includes improvements to the Parameter Embedding feature, which allows for more efficient query plan caching for parameter sensitive queries. With this feature, SQL Server can embed parameter values directly into the query plan, which can help to improve plan reuse and reduce compilation overhead.

For example, consider a query that retrieves all orders for a specific product:

SELECT *
FROM Sales.Orders
WHERE ProductID = @ProductID

With Parameter Embedding in SQL Server 2022, the query plan can be cached and reused for multiple executions of the same query, with different parameter values. This can help to reduce compilation overhead and improve performance.

Overall, the improvements to the Parameter Sensitive Plan optimization feature in SQL Server 2022 are designed to improve the performance of parameter sensitive queries, which can have multiple execution plans depending on the specific parameter values used. These improvements leverage vectorized processing, dynamic memory allocation, and improved plan caching to improve query performance for parameter sensitive queries.

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