memory pressure err messages..

  • hi all,

    we have SQL2008 (10.0.2757) installed on a Window2008 server which is up for almost 8 months with 32G RAM, SQL server uses 28G RAM (min max server memory). for the last few days we are getting the followings errors seldomly. no other error is found. What is the reason for these messages and how to resolve.

    AppDomain 33 (master.dbo[runtime].63) created.

    AppDomain 32 (master.dbo[runtime].61) unloaded.

    AppDomain 32 (master.dbo[runtime].61) is marked for unload due to memory pressure.

    Regards,
    MShenel

  • CLR uses memory outside of the buffer pool, ie outside of that 28GB you have reserved for the buffer pool.

    I suggest you drop the max memory setting down a little and see if that helps.

    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
  • so 4G may not be enough for OS and CLR executions. how to check CLR memory usage?

    Regards,
    MShenel

  • -- credit to Bob Beauchemin: http://social.msdn.microsoft.com/Forums/en-US/sqlnetfx/thread/bbc1c753-c5df-4d52-a567-c982cf506051

    SELECT SUM(pages_allocated_count) / 128.0 AS CLR_memory_MBs

    FROM sys.dm_os_memory_objects

    WHERE type LIKE '%CLR%' ;

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • the query returns 27 MB but dbcc memorystatus displays as below, MEMORYCLERK_SQLCLR (6G reserved) is that normal?

    MEMORYCLERK_SQLCLR (node 0) KB

    ---------------------------------------- -----------

    VM Reserved 6315188

    VM Committed 203504

    Locked Pages Allocated 0

    SM Reserved 0

    SM Committed 0

    SinglePage Allocator 1720

    MultiPage Allocator 25480

    (7 row(s) affected)

    MEMORYCLERK_SQLCLRASSEMBLY (node 0) KB

    ---------------------------------------- -----------

    VM Reserved 0

    VM Committed 0

    Locked Pages Allocated 0

    SM Reserved 308

    SM Committed 308

    SinglePage Allocator 0

    MultiPage Allocator 0

    Regards,
    MShenel

  • Depends. What are you doing in those CLR assemblies?

    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
  • And did you catch the CLR processes in the act? SQL Server dynamically allocates and deallocates that memory as needed so it can fluctuate wildly. It may be a good idea to setup a little scheduled job to capture this information every so often so you can compare how it moves over time, and also see the spikes.

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • i have checked few times today, but the value does not seem to be fluctuating, it is still 27M, but good idea to log the values for a week or so to know how it behaves.

    Regards,
    MShenel

  • 27M is not a lot IMO, not enough to create pressure in and of itself. What else is running on your server besides SQL Server? Do you use a lot of Linked Servers. If you want to get to the bottom of it leave all as is and continue investigating...if you want to simply relieve the memory pressure Gail's recommendation to lower the max memory setting for the SQL instance is a good place to start.

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • we are using linked servers but not much, only when there is a need for historycal data application uses linked server to retrive from another server, but most of the transactions are local. to releave the memory pressure i have already decreased max&min server memory 2G. just in 2 days free memory droped to 900M. Server hosts application as well SQL server.

    Regards,
    MShenel

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