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Memory Leak SQL 2008 R2 64 bit?


Memory Leak SQL 2008 R2 64 bit?

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SQL Galaxy
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TotalServerMemoryMB - 3270.125000


For the Lock page memory enable
---------------------------------
Lock Pages in Memory is a setting that can be set on 64-bit operating systems that essentially tell Windows not to swap out SQL Server memory to disk. By default, this setting is turned off on 64-bit systems,

Yes, that is correct, lpim is off by default but you have it turned on and you still have not told us why you enabled it.



for this reason enable LPIM in x64 operating system.

SQL service accounts can use a process to keep data in physical memory, preventing the system from paging the data to virtual memory on disk. also memory may boost performance when paging memory to disk is expected.
Orlando Colamatteo
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ananda.murugesan (9/11/2012)
TotalServerMemoryMB - 3270.125000

Thank you. This confirms what was mentioned before. At present there are no indicators that anything out of the ordinary is occurring in terms of how much memory SQL Server is using on your server.

For the Lock page memory enable
---------------------------------
Lock Pages in Memory is a setting that can be set on 64-bit operating systems that essentially tell Windows not to swap out SQL Server memory to disk. By default, this setting is turned off on 64-bit systems,

Yes, that is correct, lpim is off by default but you have it turned on and you still have not told us why you enabled it.



for this reason enable LPIM in x64 operating system.

SQL service accounts can use a process to keep data in physical memory, preventing the system from paging the data to virtual memory on disk. also memory may boost performance when paging memory to disk is expected.

There is a great debate about this in the SQL Serevr community. Some prefer to enable lpim on x64 Windows Server 2008 R2 running SQL Server 2008 R2 by default, and others prefer (including myself) to leave lpim disabled unless the database server exhibits specific behavior that signals there may be a benefit to enabling lpim.

Here is a good primer on the debate and one of many articles and my own experience that helped shape my opinion: Great SQL Server Debates: Lock Pages in Memory (12 December 2011) by Jonathan Kehayias

When SQL Server approaches 7.5 GB do you start to see system instability or messages entering the SQL Server Error Log signifying the server is under memory pressure? If not then you should be happy with your server configuration. If so, please post those messages here.

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SQL Galaxy
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Thanks for reply

I do have a question though.

Server OS’s are x64, and even though I have set the value for LPIM with the service account, I have never seen a message in the SQL log stating “Using locked pages for buffer pool” on any of the servers. Did I miss something?


I have noticed before enable LPIM in this box, In Task manger showing sqlservr.exe consuming 6.4 GB constantly and exceeds max memory setting. periviously I have setting max memory 5 GB, but sql server is not using max level. after that I have enabled LPIM and setting max memory 6114 MB.

Performance Tap in task manager why 7.5 GB consuming physical memory using after restarted SQL services, it was totaly reduced and now comsuming 4.55 GB only...thats what I have mention first post memory leak sql 2k8 r2.

OS level (Win 2008 R2 64 bit)there is no service pack installed, It is RTM. Does SP is require to be installed on OS side?

thanks
GilaMonster
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ananda.murugesan (9/11/2012)

Performance Tap in task manager why 7.5 GB consuming physical memory using after restarted SQL services, it was totaly reduced and now comsuming 4.55 GB only...thats what I have mention first post memory leak sql 2k8 r2.


There is no memory leak.

SQL uses as much memory as it needs up to max server memory + a bit for the non-buffer memory. All that the 4.5 GB now tells us is that SQL has only needed 4.5 GB of memory since the restart. Everything you've shown so far shows a SQL Server that's working fine and as expected.

Again, don't use Task Manager to show SQL's memory usage, it shows incorrectly (fault of Task Manager, not SQL Server) if locked pages is enabled.


Gail Shaw
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Thanks

one final clarifications, still I am not getting conclusion about LPIM setting.

1.SQL SERVER 2008 on top of Windows 2008 enterprise edition both x86 and x64

2.SQL SERVER 2008 R2 on top of Windows 2008 R2 enterprise edition both x86 and x64

Which & when condition needs to be enable LPIM for both environments?
GilaMonster
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Did you read the article that Opc linked?

opc.three (9/11/2012)
Here is a good primer on the debate and one of many articles and my own experience that helped shape my opinion: Great SQL Server Debates: Lock Pages in Memory (12 December 2011) by Jonathan Kehayias



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
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