what lock pages in memory option does.

  • Hi i want to know what lock pages in memory option does.

    i donot gets it wording " Windows not to swap out SQL Server memory to disk ".

    can some explain in lay men`s terms

    by "sql server memory" does it means RAM and by disk does it means secondary storage (or harddrives).

    And when it should be used

  • The operating system works with memory and paging file. The paging file is located on the disk, and when there is not enough physical memory left, the operating system can use the paging file and move data from the physical memory to it. When it will need that data, it will have to read it from the disk. The problem is that disk is a lot slower then the physical memory. If SQL Server's cache will be stored on the disk instead of the on the physical memory, you'll have a huge performance problem. When you grant SQL Server's service the right to lock pages in memory, the operating system won't be able to move memory pages that are used by SQL Server to the paging file and your are guaranteed that SQL Server will not use the paging file.

    Adi

    --------------------------------------------------------------
    To know how to ask questions and increase the chances of getting asnwers:
    http://www.sqlservercentral.com/articles/Best+Practices/61537/

    For better answers on performance questions, click on the following...
    http://www.sqlservercentral.com/articles/SQLServerCentral/66909/

  • Adi Cohn-120898 (7/22/2013)


    The operating system works with memory and paging file. The paging file is located on the disk, and when there is not enough physical memory left, the operating system can use the paging file and move data from the physical memory to it. When it will need that data, it will have to read it from the disk. The problem is that disk is a lot slower then the physical memory. If SQL Server's cache will be stored on the disk instead of the on the physical memory, you'll have a huge performance problem. When you grant SQL Server's service the right to lock pages in memory, the operating system won't be able to move memory pages that are used by SQL Server to the paging file and your are guaranteed that SQL Server will not use the paging file.

    Adi

    thanks for your reply but when u say physical memory does it means RAM

    and by disk u mean harddisk

  • Yes. When I say physical memory I mean RAM and when I say disk I mean harddisk. Sorry, English is not my native language:-)

    Adi

    --------------------------------------------------------------
    To know how to ask questions and increase the chances of getting asnwers:
    http://www.sqlservercentral.com/articles/Best+Practices/61537/

    For better answers on performance questions, click on the following...
    http://www.sqlservercentral.com/articles/SQLServerCentral/66909/

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