SQL Server Performance

NT4/SQL7 Memory Usage Inquiry

Discussion in 'Performance Tuning for DBAs' started by mar, Jan 14, 2003.

  1. mar New Member

    I am running Windows NT 4.0 EE SP6 with SQL 7.0 SP3 -- dedicated(Clustered Active/Passive). It has dual PIII 550 Mhz Xeon processor and 4 GB RAM (/3GT). It is running and ERP system with 60 users with about 20GB of database. I was monitoring the Physical Memory (K) everyday in the "Windows NT Task Manager" when I noticed that in less than two days, the "Available Memory" drops from 4GB down to 750MB. I've also noticed that the memory never rises even if users have logged off for several hours. As I checked the "Processes Tab", I noticed that the sqlservr.exe is using an average of 2.88GB of memory.

    Is this normal?
    Any suggestion?

    Thank you in advance.
  2. Argyle New Member

    It's normal. SQL Server will eventually use all the memory that it has been given if it can benefit from it. SQL Server will not release it back to the operating system unless another process or application is activly requesting more memory.

    When you have say 2GB of memory you might want to limit the SQL Server to only use max 1.8GB or 1.9GB so that there always is memory left for the operating system and other stuff. But when you have 4GB ram with the 3GB switch then I see no problem letting SQL Server use 3GB if it wants it.

    /Argyle
  3. satya Moderator

    Also check the memory counters using PERFMON and other hardware counters also, this will give exact performance details for the server.

    Satya SKJ
  4. bradmcgehee New Member

    Assuming you are still running the default dynamic memory settings, SQL Server will automatically take all the available RAM, if it needs as, as Argyle has said. Generally speaking, if the available memory is greater than 4MB, and in your case, it is, memory should not be a problem. Another way to check this for sure is to find out what your buffer hit cache ratio is. If it is over 99%, you definitely do not have any memory bottlenecks at the present.


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    Brad M. McGehee
    Webmaster
    SQL-Server-Performance.Com
  5. mar New Member

    I appreciate your inputs.

    It is really a great help.

    Thank you guys and more power.

    Mar

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