Increasing SQL Server resource monitor CPU overhead

Chris Hutchings 1 Reputation point
2021-05-20T09:11:45.37+00:00

I have a SQL Server 2019 instance (CU10) sitting on an Azure windows 2019 VM.

Server has 28GB of RAM. Min and Max Server Memory are set to 24GB. Lock pages in memory is set. Page file is set to 4GB.

When we start SQL Server baseline CPU utilization overhead is approximately 10 percent.

After a few hours we get a very clear jump whereby baseline CPU utilization jumps to 20 percent.

This can be mapped to the background sql server 'resource monitor' system process via procmon and dmv checks.

The below graph clearly illustrates when this kicks in:

![98272-image.png][1]

Once this has started this overhead simply persists until we restart SQL Server.

This looks very similar to a previous issue on older versions of SQL where MS fixes had to be applied. Was wondering is this a new bug with SQL 2019 or other ?

Any and all advice welcome !

Thanks.

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  1. CathyJi-MSFT 21,116 Reputation points Microsoft Vendor
    2021-05-21T08:53:22.18+00:00

    Hi @Chris Hutchings ,

    In Microsoft SQL Server 2008, you see that the CPU usage of the resource monitor is very high when the virtual memory is running low on the server. Did you monitor the memory usage of your SQL server? You can get the memory usage from SSMS Memory Consumption report.

    Refer to the blog High CPU consumed by Resource Monitor due to low virtual memory and Finding Resource Usage Details in MSSQL to get more detail information.

    >Was wondering is this a new bug with SQL 2019 or other ?

    I could not reproduce your issue in my environment.


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  2. Chris Hutchings 1 Reputation point
    2021-05-25T10:23:31.703+00:00

    Thanks @CathyJi-MSFT . Looks like this has fixed the issue. 2019 OS simply more hungry for memory by looks of it. TVM !