SAP Basis Tech Supports

Symptom

This note provides information about the integrated ITS as well as information about the memory requirement in the application server.
Other terms

ITS, SAP GUI for HTML, global_area_MB, HTTP_OUT_OF_EMGLOBAL_MEMORY
Reason and Prerequisites

The system log (Transaction SM21) contains the following errors:
- W0B | SAP GUI for HTML, memory unavailable, increase size of profile parameters
- Message ITS_P, 027, new session rejected due to memory bottleneck
The work process trace file contains the following entries:
- *** ERROR => EmIAllocMmResourceEg: EgAlloc(5243122) failed 5
- *** ERROR => ipl_Malloc EmAlloc(5242890) returns 7
*** ERROR => diag: Memory of 5242882 bytes allocation failed,
increase em/global_area_MB
Solution

Increase the size of the em/global_area_MB parameter.
If you are using the standard implementation of the extended memory on UNIX, increase the em/initial_size_MB parameter by the same amount as you increase em/global_area_MB.
If you are using the special implementation of the extended memory on AIX (ES/TABLE = SHM_SEGS parameter) and the sum total of em/global_area_MB and abap/shared_objects_size_MB exceeds 250MB, increase the size of the ES/SHM_SEG_SIZE parameter to 1024. You must use a 64-bit kernel to make this setting.
For platforms with a map implementation of the extended memory (Windows, Linux), the size of the EM address area (em/address_space_MB parameter) must be increased accordingly (where necessary).
Estimated memory requirement for integrated ITS:
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The default setting of the em/global_area_MB parameter is correct for systems that do not use the integrated ITS. If you want to use the integrated ITS (integrated SAP GUI for HTML or Internet Application Components), adjust the em/global_area_MB parameter to your requirements.
The memory required by ITS is divided into the memory for the ITS application (preparsed templates) and the memory required by each session.
Memory requirement for the SAP GUI for HTML
- SAP GUI for HTML application (preparsed template) approximately 10 MB per language and browser
- SAP GUI for HTML session, approximately 3 MB per session.
Example: Calculation of the memory required for the SAP GUI for HTML with 50 sessions in the languages DE and EN. The SAP GUI for HTML is accessed using the Explorer (IE) and Navigator (NS) browsers. The old value of the em/global_area_MB parameter is 64.
em/global_area_MB =
64 MB (old value of global_area_MB) +
40 MB (preparsed templates, 4*10MB, DE(IE+NS),EN(IE+NS)) +
150 MB ( 3MB * 50 sessions )
——————————————————–
254 MB total
+ 51 MB 20 % reserve of 254MB
——————————————————–
305 MB ( em/global_area_MB)
===========================================================
Result: The entire memory requirement for the SAP GUI for HTML with two browsers, two languages and 50 session users is approximately 190 MB. The em/global_area_MB parameter should be set to at least 305 MB (old value 64MB + 190 MB SAP GUI for HTML + 51 MB 20% reserve).
To calculate the memory requirement for other integrated ITS applications or Internet Application Components (IACs), proceed in the same way.
You can use the SITSPMON report to view the actual memory requirement of the ITS. For the report to display the memory consumption, you must set the itsp/memory_check parameter to 1. Remember that the preparsed trees are available once for each language, which is also the case with SAP GUI for HTML.
Large installations or numerous sessions:
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If a large number of sessions are to be configured, bottlenecks occur in the process address space (2 GB) of the Web AS work process. You can only avoid this problem by configuring multiple application servers with fewer sessions on each server or by changing to 64-bit hardware because the restriction no longer exists on this type of hardware.
Since a large number of productive R/3 instances already reach the 2 GB limit without using integrated ITS, you require 64-bit hardware to use integrated ITS in a production system.
You should only operate demo or test systems that have a small number of users on 32-bit hardware, after first estimating the memory required.
Reduced memory requirement with Web AS Kernel 700
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In Release 700, the memory requirement of the integrated ITS has been significantly reduced. Storage of the preparsed templates has been optimized, so that (for example) the memory requirement of the SAP GUI for HTML has been halved (from 10MB preparsed templates in Release 640 to 5MB in Release 700).
Furthermore, the preparsed templates are no longer language-dependent, meaning that the memory requirement no longer depends on the number of languages you use. Depending on the application, this reduction of required memory allows the extended use of the integrated ITS on 32-bit hardware.