Sql server is using memory more then there max memory setting?

Question

Hi All,
today i have faced the different issue..........
we have one SQl server 2008 prod server... it have memory issue actually  total server memory is 8GB and we have allocated the 6 GB to SQL server,we checked the server no open trans and dont have running jobs also,one database is using the memory high(no
open trans)... but Sql server has used 6.5 GB (6 GB) and total server used memory is reached to 7.89 GB.
Please tell me how to find the most costly query in particular database wise and sql server internally behavior ?
how to troubleshot the  above issue?
please post the your valuable answers ASAP...
Thanks,
RAM

Answer 1

Please refer to what Olaf said briefly.Buffer pool in SQL server only caters to memory requests which requires pages <8 KB . Almost all requests are satisfies by buffer pool and generally request for memory is small and so buffer pool satisfies the requests.
However there are some direct memory allocation by windows API which is done by windows for requests which  requires memory greater than 8 KB. This memory wont come from buffer pool and this would be counted in memory utilized by SQL server. SQL
CLR,XML, linked Server, all takes memory outside buffer pool in SQL Server 2008. This behavior changed in 2012 so my statement only applies to SQL server 2005/2008 and 2008 R2.
I would run below to check SQL server memory utilization.
select
(physical_memory_in_use_kb/1024)Memory_usedby_Sqlserver_MB,
(locked_page_allocations_kb/1024 )Locked_pages_used_Sqlserver_MB,
(total_virtual_address_space_kb/1024 )Total_VAS_in_MB,
process_physical_memory_low,
process_virtual_memory_low
from sys. dm_os_process_memory
I am sure you must be using some features mentioned above.You were worried that even though there is no query running on SQL server it has still holded up the memory. This is default behavior and this is how memory management in SQL Server works. It will
not release memory untill SQLOS asks it to do so which is told by windows OS thorugh some flag that it is facing memory pressure.
Please read below for more details on memory. There is section to test whether system is facing memory crunch please read that as well.
http://social.technet.microsoft.com/wiki/contents/articles/22316.sql-server-memory-and-troubleshooting.aspx
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