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1、SAP Memory Management (an Overview)2021/8/22021/8/21 1SAP Memory ManagementSAP Memory areas overview :- SAP Buffer- SAP Roll Memory- SAP Extended Memory- SAP Heap Memory- SAP Paging Memory- Fixed Local Memory of the SAP work Process Main factors in configuring SAP Memory :- Physical Main Memory (RAM
2、) give attention to ratio between physical and virtual memory- Operating system options and restrictions compare between 32 and 64 bit system architecture2021/8/22021/8/22 2Memory management fundamental :The word “memory” virtual memory physical main memory + swap space local memory + shared memoryT
3、he maximum amount of virtual memory that can be allocated is limited by two variable :- Result of physical hardware restriction- Maximum address space permited by operating system The Operating System manages two type of memory :-Local memory allocated precisely to one operating system process-Share
4、d memory accessible to multiple operating system process 2021/8/22021/8/23 3Reffered : Data which is generated by transaction process Variables, Internal table & screen list New sesion = new user context Data is stored independently in different memory areas Stored in SAP roll memory, SAP extended m
5、emory, & SAP Heap MemoryUser ContextSesions divide into :External sesion opened explicitly by user Internal sesion Opened implicitly by programsubmit,calltransaction,calldialog,callscreen,callfunctioninupdatetask,callfunctioninbackgroundtask,andcallfunctionstartingnewtask.2021/8/22021/8/24 4Pres. se
6、rverSAP Application SeverDB ServerSAP GUISAP Extended MemoryDispatcher QueueSAP Roll MemorydispatcherTablebufferProgrambufferDDIC BufferWork ProcessWork ProcessWork ProcessDB ProcessDB ProcessDB ProcessDatabasebufferProcess Flow2021/8/22021/8/25 5SAP Roll Memory Local SAP Roll area of work process-
7、The initial part of user context stored - Each SAP work process can only access its own roll area Shared SAP Roll Area- Accessible to all of instance work processes- Buffer to temporary keep user context when a user is assigned to new work process- Roll in : copying user context from shared roll are
8、a to local roll area - Roll Out : copying user context from local roll area to shared roll area 2021/8/22021/8/26 6Roll fileRoll (local)Roll Buffer (shared)Roll In / Roll Outrdisp/roll_SHMrdisp/roll_MAXFSztta/roll_firstztta/roll_areaRoll buffer (shared memory)Roll area (local)Roll file (disk)Roll ar
9、ea (local)Work Process1Work Process2copycopy2021/8/22021/8/27 7SAP Roll area parameters - ztta/roll_first: First amount of roll area used in a dialog WP- ztta/roll_area : size of the local SAP Roll area in the work process- rdisp/ROLL_SHM : size of SAP roll Buffer- rdisp/ROLL_MAXFS: size of entire s
10、hared SAP roll area2021/8/22021/8/28 8SAP Extended Memory Shared memory which mostly of user context stored All SAP work process can edit stored user context directly Roll in rather only copied the address (pointer) of where a user context located on the SAP extended memory. makes roll process much
11、fasterztta/roll_extensionem/initial_size_MB2021/8/22021/8/29 9SAP Extended Memory main parameters : em/initial_size_MB : size of SAP extended memory allocated when the SAP instance starts up em/blocksize_KB : size block which split SAP Extended Memory ztta/roll_extension : maximum size of a user con
12、text in the SAP Extended memory 2021/8/22021/8/21010SAP Heap Memory Area which allocated variably as local memory as required. Released after a transaction is complete. SAP Heap Memory main parameters : abap/heap_area_dia : quotas oh SAP heap memory that a dialog process can allocated. abap/heap_are
13、a_nondia : quotas oh SAP heap memory that a nondialog process can allocated. abap/heap_area_total : size that can be allocated in total by all work process. abap/heaplimit : Workprocess restart limit of heap memory Heap Memory (local)abap/heap_area_(non)diaabap/heap_area_total2021/8/22021/8/21111Seq
14、uence in which memory is allocated (dialog work process) : User-Independent DataRoll memory to zttz/roll_firstRoll memory to zttz/roll_extensionRoll memory to zttz/roll_areaRoll memory toabap/heap_area_dia1234User ContextCopying data during context changeMapping the data during context change- Data
15、stays in work process- No context switch possible- Work process in private mode2021/8/22021/8/21212User-Independent DataRoll memory to zttz/roll_extensionRoll memory to zttz/roll_areaRoll memory toabap/heap_area_dia123User ContextCopying data during context changeMapping the data during context chan
16、ge- Data stays in work process- No context switch possible- Work process in private modeSequence in which memory is allocated (non-dialog work process) : 2021/8/22021/8/21313SAP EG Memory and SAP Paging Memory Data can be stored globally between user contextSAP Extended Global Memory Used to store d
17、ata across user context Allows fast & copy-free switching based on mapping. Substracted from SAP Extended Memory to calculate the remaining storage space configured using em/global_area_MB parameters2021/8/22021/8/21414SAP Paging MemoryObject that stored in the SAP Paging Memory : ABAP data cluster
18、stored temporarily with ABAP statement IMPORT/EXPORT FROM/TO MEMORY Parameter transferred when programs and transaction calledSUBMIT REPORT, CALL TRANSACTION, CALL DIALOG, CALL SCREEN, CALL FUNCTION IN UPDATE TASK, CALL FUNCTION BACKGROUND TASK, CALL FUNCTION STARTING NEW TASK Data extracts created
19、by statement EXTRACT (up to basis 4.5) SAP Paging Memory Main Parameters : rdisp/PG_MAXFS : Size of SAP Paging Memory rdisp/PG_SHM : Size of SAP Paging Buffer (shared memory)Error caused by SAP Paging Memory :TSV_TNEW_PG_CREATE_FAILED SYSTEM_NO_MORE_PAGING2021/8/22021/8/21515SAP paging bufferSAP buf
20、fers (contains e.g SAP Programs)Extended Memory (User Context)ServerSAP roll bufferGlobal Memory (shared memory)Local memoryAdditional local heap memory (if required)LocalmemoryLocalmemoryLocalmemorySAP Roll FileSAP Paging File WorkProcessWorkProcessWorkProcess1 : n1 : 12021/8/22021/8/21616Configuri
21、ng & Monitoring SAP Memory Areas Main Objective : Performance StabilityMain Factors to be considered : Physical Main Memory (RAM) Swap space or paging file of the operating system Operating system restriction2021/8/22021/8/21717Next points to be considered : Total Main Memory Requirement Number of C
22、omputer Several SAP instances per computer SAP extended memory and roll buffer Memory for SAP work process Database InstanceZero administration memory magement : PHYS_MEMSIZE parameter defines how much of a computers total physical memory should be used for the SAP instance.2021/8/22021/8/21818User
23、IndependentWP LocalSAPBuffers(Shared)User ContextRollMemory(Shared)SAP Extended Memory(Shared)SAP Heap Memory(local)em/initial_size_MBabap/heap_area_(non_)diaAddress SpaceSAP Work ProcessAddress Space Restriction (Unix)2021/8/22021/8/21919User IndependentWP LocalSAPBuffers(Shared)User ContextRollMem
24、ory(Shared)SAP Extended Memory(Shared)SAP Heap Memory(local)em/address_space_MBabap/heap_area_(non_)diaAddress SpaceSAP Work ProcessSAP Extended Memory Totalem/initial_size_MBAddress Space Restriction (Windows)2021/8/22021/8/22020Assistance With TroubleshootingError because of incorect memory area c
25、onfiguration : Operating System can not start because the operating system cannot provide the requsted memory area Session terminations User is logged off ABAP Program termination. Four error factors : Program errors (e.g endless loop) SAP Profile parameters are set incorectly The Swap Space on the
26、operating system is not large enough Configuration parameters of the operating system are set incorectly or OS limits have been reached.2021/8/22021/8/22121ABAP Program Termination : The memory of user context is used up : STORAGE_PARAMETERS_WRONG_SET, SYSTEM_ROLL_IN_ERROR, TSV_TNEW_BLOCKS_NO_ROLL_M
27、EMORY, TSV_TNEW_PAGE_PAGE_ALLOC_FAILED, TSV_TNEW_INDEX_NO_ROLL_MEMORY System can not create the program buffer because there is not not sufficient shared memory at that time PXA_NO_SHARED_MEMORY The Program encounters a memory bottleneck during an operation in the database interface DBIF_RTAB_NO_MEM
28、ORY, DBIF_RSQL_NO_MEMORYThe Program encounters a memory bottleneck during sorting. EXSORT_NOT_ENOUGH_MEMORYAttemp to create error log fails after a terminated program due to lack of memory. RABAX_CALLING_RABAXThe SAP paging memory is used up SYSTEM_NO_MORE_PAGING, TSV_TNEW_PAGE_ALLOC_FAILEDThe memory for SET/GET parameter (SPA/GPA memory) is used up. SET_PARAMETER_MEMORY_OVERFLOW Volume limit of memoy allocated to single call (ztta/max_memreq_MB) is set too low SYSTEM_NO_ROLL2021/8/22021/8/22222- End of Presentation -2021/8/22021/8/22323部分资料从网络收集整理而来，供大家参考，感谢您的关注！
