SQL Server Wait Type: RESERVED_MEMORY_ALLOCATION_EXT

Wait statistics, in the context of SQL Server, refer to the amount of time that a query spends waiting to access data in the database. When a client application requests data from the database, the request is placed in a queue and the client application must wait for its turn to access the data. The time that the query spends waiting is called a “wait” and is tracked by SQL Server. This information can be used to identify potential performance bottlenecks and optimize the performance of the database. Wait statistics are commonly used by database administrators to diagnose and troubleshoot performance issues in SQL Server.

In order to ensure that data is accessed efficiently and consistently, SQL Server uses various “wait types” to manage how requests for data are processed.

One of these wait types is called RESERVED_MEMORY_ALLOCATION_EXT. This wait type is triggered when SQL Server is attempting to allocate memory from the buffer pool extension (BPE) and is waiting for the operation to complete.

The buffer pool is a memory area that is used by SQL Server to store data pages that have been read from disk. The buffer pool extension is an additional area of memory that can be used to store data pages that do not fit in the regular buffer pool.

When a SQL Server process needs to allocate memory from the buffer pool extension, it sends a request to do so. The request is then processed, which can take some time depending on the amount of memory being allocated. In the meantime, the SQL Server process waits for the allocation to complete before it can continue with its work. This waiting is what is known as a RESERVED_MEMORY_ALLOCATION_EXT wait.

While the RESERVED_MEMORY_ALLOCATION_EXT wait type is generally not a cause for concern, it can sometimes indicate a performance issue if it is occurring frequently or for long periods of time. In these cases, it may be necessary to investigate the cause of the issue and take steps to improve performance, such as optimizing the memory allocation process or increasing the systems resources.

Overall, the RESERVED_MEMORY_ALLOCATION_EXT wait type is an important part of how SQL Server manages memory allocation from the buffer pool extension. By understanding this wait type and its potential impact on performance, database administrators can ensure that their systems are running efficiently and effectively.

More details avilable on this wait type here: http://DatabaseHealth.com/Waits/RESERVED_MEMORY_ALLOCATION_EXT.html

Do you have a favorite tool for monitoring your wait statistics on SQL Server over time? This is something that you can use Database Health monitor to do. More details at http://DatabaseHealth.com.

If you are having performance issues associated with this wait type and need some help, please contact us with our 30 minute consultation link.