XADM: Resource Failure Error on Computers with More Than 800 MB of RAM

• Microsoft Exchange Server, version 5.5

SYMPTOMS

On a very active Exchange Server computer with more than 800 megabytes (MB) of RAM, Exchange Server may start logging the following error message:

Event ID: 1160
Source: MSExchangeIS
Type: Error
Description: Database resource failure error Out of memory occurred in function "JTAB_BASE::EcCreateIndex" while accessing the database.

CAUSE

Exchange Server is attempting to allocate more virtual memory than is available within the process.

The Windows NT virtual memory address space is 4 gigabytes (GB) in size for each process. This implies that no matter how much physical memory is installed, a single process has access to only 4 GB of address space. In addition, Windows NT divides virtual memory into that which is used by the kernel, and that which is accessible to user-mode (for the application). In standard Windows NT Server 4.0, a user-mode application (like Store.exe) has access to 2 GB of virtual memory, and the kernel uses the other 2 GB. In Windows NT 4.0 Enterprise Edition, a user-mode application has access to 3 GB of virtual memory, and the kernel gets 1 GB.

All memory allocations for a process come out of the 2 or 3 GB available in the address space. The address space is not empty when a process loads, many elements take up space in it immediately. The code itself is loaded into virtual memory (Store.exe and all the DLLs); a system heap is allocated from this virtual memory; for every thread created, a 1 MB virtual memory allocation (typically) is created for the thread stack, and so on.

The net result is that for an individual process, the process will not be able to allocate a full 2 or 3 GB of virtual memory because some of it is in use.

The Exchange Server 5.5 Performance Wizard (Perfwiz) makes calculations about how much virtual memory will be used by using the amount of physical RAM as an indicator. When 2 GB of RAM is physically installed, Perfwiz will assume that it can allocate up to 2 GB of virtual memory for a process. This amount of virtual memory may not be free in a process's address space, so attempting to allocate this much virtual memory may fail.

RESOLUTION

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, please see the following article in the Microsoft Knowledge Base:

Q191014 XGEN: How to Obtain the latest Exchange Server 5.5 Service Pack

STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 3.

Additional query words: performance optimizer

Keywords : exc55 EXC55SP3Fix
Version : winnt:5.5
Platform : winnt
Issue type : kbbug