December 1, 2021

Why does SQL Server Consume So Much Memory

According to the company, Microsoft SQL Server is a relational database management system (RDBMS). In relational databases, all SQL Servers use the SQL programming language, which is well-known and widely used. Microsoft created SQL Server's Transact-SQL implementation, also referred to as T-SQL, used by SQL Server. A number of programming constructs not found in SQL are also included in T-SQL.

Overall, SQL Server is an important component of Microsoft's data platform, as it provides exciting levels of performance for mission-critical applications through in-memory technologies, faster insight and perspective from any type of data with well-known tools such as Excel, and a platform for the development of on-premises and cloud-based solutions, as well as a platform for solution management.

SQL Server has been in existence for 32 years at the time of writing. It is a mature product that will almost certainly not meet all of the needs of every development team, but it does cover the vast majority of the requirements that a development team may have for data access.

A significant number of services that we use on a daily basis rely heavily on SQL Server databases. These services include financial institutions, bookmakers, government agencies, the medical industry, and well-known websites.

SQL server features and benefits

High availability is a standard feature for SQL Servers, allowing for high uptime and faster switching. All of this is accomplished without depleting system memory. SQL Server's database and analytics engines now have more flexibility and ease of use thanks to the addition of in-memory capabilities. Probably the most notable feature is that it integrates seamlessly with the Microsoft Server family of server platforms.

How much memory does the SQL server use?

SQL Server uses about 87.5% of the RAM on my server. Many performance issues have arisen as a result of this, including slowness. When we start looking into this issue, we can find a lot of dead ends. A common solution found on the internet is to increase the SQL Server maximum execution time. A lot of work has gone into this, and it shows. If you hire a developer, you might get the help you need with this.

SQL Server will consume all of the available memory. By default, that number corresponds to the total amount of numeric memory available on your computer. As a result, your perceptions are correct. To put it another way, if you give SQL Server 24 GB of memory, it will make every effort to make the most of that memory. When SQL Server and the operating system are competing for resources, poor performance is an inevitable byproduct.

SQL Server's buffer pool is limited by the maximum server memory limit configuration set in the server's configuration (pretty much where it stores the data pages and the procedure cache). The buffer pool is not the only memory worker in SQL Server; there are a number of other memory workers as well (for versions 2008 R2 and later). However, this will always be the application with the highest memory requirements.

The Microsoft SQL Server Database Engine's buffer pool is limited by the server's minimum and maximum memory settings.

Server configuration options

By customizing the minimum and maximum server memory choices for a specific SQL Server instance, you can alter the amount of memory (measured in megabytes) that SQL Server Memory Manager manages. The memory requirements of SQL Server can be adjusted dynamically based on the available resources on the system.

To set a fixed amount of memory, follow these steps:

  • Right-click a server in the Object Explorer, and select Properties from the context menu.
  • Select the Memory node from the drop-down menu.
  • Under Server Memory Options, enter the amounts you want for Minimum Server Memory and Maximum Server Memory in the appropriate fields.

If you want SQL Server to be able to change its memory requirements dynamically in response to available system resources, use the default setting. In the default configuration, the minimum server memory is set to 0 megabytes, and the maximum server memory is set to 2147483647 megabytes by default (MB).

Freeing up the server

SQL can be configured to only use a specific amount of RAM if necessary. Otherwise, it will consume the maximum amount of resources. This is the standard procedure after thoroughly investigating the server and confirming that SQL Server consumes 9GB of the server's total 10GB of RAM capacity. Anyone would limit the amount of memory available for SQL to, say, 6GB in order to avoid crashing the server and to give it some breathing room. Moreover, if you look at the performance, you will notice that it is in compliance.

Optimal consumption

Although the previous solution may be sufficient to get us out of trouble, it is clear that the ideal solution would be to discover a way to determine exactly how much memory each Database (DB) consumes in order to determine how much memory the SQL Server instance requires. Easy. It is only necessary to run a SQL query in order to see it.

Following our observation of total RAM memory, we can add the total of 'db buffer MB' and see how much RAM memory SQL has consumed in total. As an example, if we lower the SQL limit to 9GB and run the query, we can see that the databases only consume 3GB of RAM memory, which is significantly less than the previous example.

As a result, the initial hypothesis about SQL Server's excessive memory consumption has been proven correct. Despite the fact that the databases consume only 3GB of memory, if we limit the instance to 6GB, SQL Server manages to make full use of the available memory. We would be talking about the act of observing one's own memories.

Real application

The most important aspect of this result is that it can be put to practical use. Given that SQL requires only 3GB of RAM to function properly, is it possible to limit SQL's RAM usage to 4GB and avoid wasting the entire allocation? Yes.

In this image, we can see the concrete consumption of a database after running a new query. Moreover, if we run this query on a regular basis and keep track of the average, we can determine whether or not the consumption fluctuates.

The importance of monitoring

In situations such as the one we are currently dealing with, the importance of monitoring becomes immediately apparent. With a historical record of SQL Server's RAM memory consumption, we can calculate a reasonable average and then set limits on how much memory can be allocated.

Monitoring enables us to develop a scale that determines maximum and minimum values, as well as their relationships. Neither the client nor the technician will receive an alarm email if either of these thresholds is exceeded, or if the application consumes more memory than is desired.

Important note

Increasing the maximum server memory for a single SQL Server instance above its recommended value may force the SQL Server instance to compete with other SQL Server instances running on the same server node for memory. In the event that you set your memory limit too low, you may experience significant memory shortages or performance issues. If you set the Maximum Server Memory parameter to a value that is too low, SQL Server may be unable to start properly.

After changing the max server memory parameter, if you are unable to start SQL Server, try starting it with the -f startup parameter and restoring the max server memory parameter to its previous value.


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