Memory Usage Question

  • Good morning Experts,

    I have two SQL Servers.These two SQL servers have about 110 GB Ram each, but

    SQL is using 98 percent of the Ram on both servers. I know that SQL will

    take what you give it, and this is normal. My question is when I install

    the application and set it to use 1gb Ram, will SQL relinquish the Ram to the new

    application, or will the server require a restart for the new application to

    acquire the Ram?

  • The application will request memory, windows will ask SQL to reduce memory usage, SQL will reduce.

    Better would be for you to go and set max server memory slightly lower to accommodate the new app.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Good morning Gail Shaw,

    When i install an application, set it to use 1GB RAM , will SQL Server grab this 1 GB RAM

  • coolchaitu (6/16/2016)


    Good morning Gail Shaw,

    When i install an application, set it to use 1GB RAM , will SQL Server grab this 1 GB RAM

    No, but it's better you set the max server memory for your sql server instance. Right click on the instance, go to Properties, then Memory and you're there. Read about the max memory set up:

    As a general base configuration, for a dedicated SQL Server machine, reserve 1 GB of RAM

    for the OS, 1 GB for each 4 GB of RAM installed from 4–16 GB, and then 1 GB for every 8

    GB RAM installed above 16 GB RAM. This means that, for a server with 64 GB RAM, the

    starting point for max server memory should be in the 54 GB range, and then tuned

    higher based on monitoring the Memory\Available Mbytes performance counter. from the book Troubleshooting SQL Server A Guide for the Accidental DBA by Jonathan Kehayias and Ted Krueger

    Igor Micev,My blog: www.igormicev.com

  • But, SQL Server can acquire more memory than what is specified in max server memory

  • coolchaitu (6/16/2016)


    But, SQL Server can acquire more memory than what is specified in max server memory

    No, the excess from the value set in the max memory setting is used by the OS and other applications.

    Even on a dedicated sql server, it uses what is set there.

    Igor Micev,My blog: www.igormicev.com

  • max server memory just controls the buffer pool, not CLR, full text,multiple other processes that run outside of the Buffer Pool memory

  • coolchaitu (6/16/2016)


    max server memory just controls the buffer pool, not CLR, full text,multiple other processes that run outside of the Buffer Pool memory

    That's why Gail advised you to decrease it a bit lower then the value obtained by a formula (if you applied any).

    I usually set the max server memory a little bit lower, because of monitoring tools, and other apps.

    Igor Micev,My blog: www.igormicev.com

  • coolchaitu (6/16/2016)


    max server memory just controls the buffer pool, not CLR, full text,multiple other processes that run outside of the Buffer Pool memory

    Those are small amounts of memory usually, few hundred MB, couple GB at most unless you're doing some really strange CLR, that's why max server memory settings are usually suggested conservative and increase if there's free memory still.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass

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