Memory Properties

Analysis Services supports the server memory properties listed in the following table. For guidance in setting these properties, see SQL Server 2008 R2 Analysis Services Operations Guide.

Values between 1 and 100 represent percentages of Total Physical Memory or Virtual Address Space, whichever is less. Values over 100 represent memory limits in bytes.

Applies to: Multidimensional and Tabular server mode, unless noted otherwise.

Properties

LowMemoryLimit
A signed 64-bit double-precision floating-point number property that defines the point at which the server is low on memory, expressed as percentage of total physical memory. When this limit is reached, the instance will start to slowly clear memory out of caches by closing expired sessions and unloading unused calculations. The server will not release memory below this limit. The default value is 65; which indicates the low memory limit is 65% of physical memory or the virtual address space, whichever is less.

TotalMemoryLimit
Defines a threshold that when reached, causes the server to deallocate memory more aggressively. The default value 80% of physical memory or the virtual address space, whichever is less.

Note that TotalMemoryLimit must always be less than HardMemoryLimit

HardMemoryLimit
Specifies a memory threshold after which the instance aggressively terminates active user sessions to reduce memory usage. All terminated sessions will receive an error about being cancelled by memory pressure. The default value, zero (0), means the HardMemoryLimit will be set to a midway value between TotalMemoryLimit and the total physical memory of the system; if the physical memory of the system is larger than the virtual address space of the process, then virtual address space will be used instead to calculate HardMemoryLimit.

VirtualMemoryLimit
An advanced property that you should not change, except under the guidance of Microsoft support.

VertiPaqPagingPolicy
Specifies the paging behavior in the event the server runs low on memory. Valid values are as follows:

Zero (0) disables paging. If memory is insufficient, processing fails with an out-of-memory error. If you disable paging, you must grant Windows privileges to the service account. See Configure Service Accounts (Analysis Services) for instructions.

1 is the default. This property enables paging to disk using the operating system page file (pagefile.sys).

When VertiPaqPagingPolicy is set to 1, processing is less likely to fail due to memory constraints because the server will try to page to disk using the method that you specified. Setting the VertiPaqPagingPolicy property does not guarantee that memory errors will never happen. Out of memory errors can still occur under the following conditions:

• There is not enough memory for all dictionaries. During processing, Analysis Services locks the dictionaries for each column in memory, and all of these together cannot be more than the value specified for VertiPaqMemoryLimit.

• There is insufficient virtual address space to accommodate the process.

To resolve persistent out of memory errors, you can either try to redesign the model to reduce the amount of data that needs processing, or you can add more physical memory to the computer.

Applies to tabular server mode only.

VertiPaqMemoryLimit
If paging to disk is allowed, this property specifies the level of memory consumption (as a percentage of total memory) at which paging starts. The default is 60. If memory consumption is less than 60 percent, the server will not page to disk.

This property depends on the VertiPaqPagingPolicyProperty, which must be set to 1 in order for paging to occur.

Applies to tabular server mode only.

HighMemoryPrice
An advanced property that you should not change, except under the guidance of Microsoft support.

MemoryHeapType
An advanced property that you should not change, except under the guidance of Microsoft support.

Applies to multidimensional server mode only.

HeapTypeForObjects
An advanced property that you should not change, except under the guidance of Microsoft support.

Applies to multidimensional server mode only.

DefaultPagesCountToReuse
An advanced property that you should not change, except under the guidance of Microsoft support.

HandleIA64AlignmentFaults
An advanced property that you should not change, except under the guidance of Microsoft support.

MidMemoryPrice
An advanced property that you should not change, except under the guidance of Microsoft support.

MinimumAllocatedMemory
An advanced property that you should not change, except under the guidance of Microsoft support.

PreAllocate
An advanced property that you should not change, except under the guidance of Microsoft support.

SessionMemoryLimit
An advanced property that you should not change, except under the guidance of Microsoft support.

WaitCountIfHighMemory
An advanced property that you should not change, except under the guidance of Microsoft support.

See Also

Configure Server Properties in Analysis Services
Determine the Server Mode of an Analysis Services Instance