I am building an application in which I plan to embed SQL Server 2012 Express as the primary datastore. When testing on my development machine (Win7-32 with 3GB RAM), I never observed the
sqlservr.exe process to use more than 1GB of RAM as I would expect from the published hardware scaling limits for the Express edition of SQL Server.
I then moved my application to a server-grade machine (Win Server 2008R2 64-bit with 16GB RAM) to evaluate its performance there and was surprised to find that the
sqlservr.exe process rapidly expanded to approximately 9.5GB of RAM and stayed there. I restarted it a couple times to see if that would have any effect, but each time, the process rapidly returned to ~9.5GB. Now I am certainly pleased to have SQL Server Express make use of my RAM, but I would like to know if this is expected behavior so that I do not come to rely on performance levels that are based on RAM usage that is incorrect.
FYI, the version of SQL Server on my server machine, according to
SELECT @@VERSION, is:
Microsoft SQL Server 2012 (SP1) - 11.0.3000.0 (X64)
Oct 19 2012 13:38:57
Copyright (c) Microsoft Corporation
Express Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)
Edit: my 9.5GB number came from the "Private Working Set" number in Task Manager. The first table of output from
DBCC memorystatus (albeit on a now idle server) is below:
PROCESS/SYSTEM COUNTS Available Physical Memory 5543616512 Available Virtual Memory 8734902411264 Available Paging File 22471094272 Working Set 9664200704 Percent of Committed Memory in WS 99 Page Faults 2627510 System physical memory high 1 System physical memory low 0 Process physical memory low 0 Process virtual memory low 0
Output from spaghettidba's suggested query on
MEMORYCLERK_SQLBUFFERPOOL 1410 OBJECTSTORE_LOCK_MANAGER 256 MEMORYCLERK_SQLCLR 38 MEMORYCLERK_SOSNODE 26 CACHESTORE_SQLCP 11
plus ~10 more smaller entries that sum to less than 30MB.