Releasing SQL Server engine memory

SQL Server typically uses available memory resources to cache data and improve performance. However, there are situations in which SQL Server may consume more memory than usual. One such scenario occurs when your server has multiple NUMA (Non-Uniform Memory Access) nodes, and SQL Server attempts to distribute memory equally across these nodes. This can lead to increased CPU usage as data is transferred between NUMA nodes.

In this article, we won't delve into the complexities of NUMA nodes, memory usage, and CPU contention. Instead, we'll focus on a practical solution for releasing SQL Server engine memory when dealing with large memory configurations, such as 1TB or more.

Releasing SQL Server Memory Efficiently

Releasing memory from SQL Server can be a delicate task, especially in large-scale environments. Simply setting the "max server memory" option may lead to engine interruption and higher CPU usage as memory is abruptly reclaimed. To avoid such issues, we'll discuss a method for gradually releasing memory, minimizing engine interruption, and reducing CPU usage.

The Gradual Memory Release Script

We can achieve a controlled memory release by using a small script. This script allows us to release memory in a controlled and incremental manner, preventing abrupt interruptions and excessive CPU usage. The script can be implemented as a stored procedure, providing a flexible solution for managing memory.

For those interested in the script, you can find it [here]. This script allows you to specify the amount of memory to release and the duration over which the release should occur.

By gradually releasing memory, you can strike a balance between optimizing memory usage and ensuring the stability and performance of your SQL Server instance.

In summary, when working with SQL Server in environments with substantial memory resources, consider the implications of memory management. Gradual memory release can help you maintain the efficiency and reliability of your SQL Server system while avoiding sudden disruptions and excessive CPU usage.

Usage:

exec AR_DecreaseSQLServerUsedMemory 524288
exec AR_DecreaseSQLServerUsedMemory 524288,500