5/30/2016How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance SAP application performance SAP TRANSACTION HOW TO RUN SAP TRANSACTION ST02 AND DO PERFORMANCE ANALYSIS IN SAP MEMORY/BUFFER AREA GALLERY | DECEMBER 15, 2012 | ERIC | 6 COMMENTS SAP transaction ST02 can be used to view SAP Buffer and memory con guration for a SAP instance and review SAP memory quotas for individual user job or process as well as current SAP buffer status, SAP memory utilization at SAP instance or user/transaction level. This post would cover following areas: 1. How to run SAP memory usage monitor and navigate through important ST02 screens. 2. How to understand SAP ST02 screens: main/summary screen or SAP memory Quota screens etc. 3. How to use SAP ST02 to do SAP memory and buffer performance analysis. 1. How to run SAP Memory/Buffer monitor and navigate through important screens of the monitor 1.1 How to start SAP Buffer/Memory monitor To start SAP Buffer/Memory monitor, you can either use menu path or run sap transaction ST02 directly. This would show buffer/memory con guration and usage for the instance where the SAP ST02 is started. After you execute SAP transaction ST02, SAP buffer and memory overview/status screen would show up: http://www.sapperf.ca/runsapst02memorymonitor/ 1/11 ca/runsapst02memorymonitor/ 2/11 .2 How to navigate through important screens of the SAP ST02 transaction. I would mention some important screens which I use most often. Use and MaxUse.sapperf.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Figure 1 – ST02 memory overview/summary You can refresh the screen to show new status. 1. http://www. Except Curr. Following screen shows menu path and hot key which you can use to access other SAP st02 screens: In following sections. all other noncon guration data are accumulated data since last startup of the SAP instance in question. 2. you can click the one you would like to review.1 How to review SAP Buffer and Memory for another instance of the SAP system If your system has more than one instance.2.3 How to navigate to mode list screen showing memory usage at user/transaction level You can bring up mode list screen from main screen (Figure 1) via following path: Details analysis menu -> SAP Memory -> Mode list http://www.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance 1. the other is for non-dialog tasks like SAP SM37 jobs.sapperf. 1. You can get the memory quota screen for single sap work process via menu Goto->SAP memory-> Quotas: Figure 2 ST02 – memory quotas for a work process 1.2.2 How to navigate to SAP quotas screen – SAP memory allocation for a single work process SAP ST02 Quota screen shows type of memory and amount allowed for a single SAP work process as well as memory allocation sequence. There are two sequences – one is for dialog type tasks like online transaction executed by a SAP user.ca/runsapst02memorymonitor/ 3/11 . you can display to another instance via following path from gure-1 screen: Environment -> RFC server or press shift+F4 key until a popup window shows up with a list of instance. SAP ST02 would bring up history screen just for the selected buffer type. SWAP difference between two dates can show the growth pattern –base on that.sapperf. History information can reveal abnormal memory usage as well as high-water mark namely “Maximum Usage” since the date when instance is started or restarted. You can access this information via following menu path or hot keys from the memory initial screen.ca/runsapst02memorymonitor/ 4/11 .2. http://www. you can double click the corresponding row in Figure-1 screen –the screen would change. on the new screen click on History Icon. Following is a part of history screen : Figure 4 – ST02 History data If you are just interested in buffer history for one buffer type. you can see whether action is needed to correct the situation.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Figure 3 – Memory usage by SAP users 1.4 How to navigate to SAP memory history screen SAP ST02 provides you history memory usage information. But the change would only come into effect after the instance is bounced. Call Statistics shows database access information. Explanation on SAP ST02 screens Here I would explain several frequent referred ST02 screens to help you understand the data presented by SAP ST02 transaction.ca/runsapst02memorymonitor/ 5/11 . It looks like straightforward. buffer sections and SAP memory section is more critical – that is what I am going to cover in following sections. Buffer section shows different SAP buffer con guration and current status. SAP has a tool to allow you to change SAP memory parameters(Extended Memory and Heap memory) dynamically –this means that your change would become effect immediately.sapperf.1 Buffer section explanation http://www. From performance point view. Following is a part of SAP memory/buffer parameter screen: You can select a pro le parameter and change it. SAP Memory section shows SAP memory con guration and current status. I have not encountered a performance case which I need “Call Statistics” data to do analysis. 2. instance startup date and snap-shot of date time. 2.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance 1.1 SAP buffer and memory overview/summary screen ST02 overview screen show information at instance level and has several sections: Top shows instance name.2.5 How to navigate to parameter screen You can check SAP memory/buffer parameters via Icon or following the menu path: Goto-> Pro le Parameters -> Current. 2.1. only eligible for Page memory and roll memory. Hitratio % Namely buffer quality =( total access – physical access)/ total access x 100%. % Free Dir = free Directory / Dir. A great book on SAP performance – SAP Performance Optimization Guide: Analyzing and Tuning SAP Systems. Size X 100%. Size Maximum number of buffer object that can be kept in the related buffer. SAP Basis. Alloc. KB Free space = allocated memory space – occupied memory space. FreeDirEnt Free Directory Entry = Directory Size – used Dir Entry. 2. Column Explanation Sap Memory Show type of SAP memory Curr. SAPCurCache SAP Cursor Cache HitRatio Applicable for ID and statement Caches.2 SAP Memory Quotas screen http://www.ca/runsapst02memorymonitor/ 6/11 . SAP Administration 2. KB Con gured or allocated memory space for the buffer type in question.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Column eld explanation Screen Field Explanation Buffer Type of buffer like nametab. Dir.1. DB Access Number of data transfers from the data base to the related buffer.sapperf. Freesp. Swap Number of buffered objects which has been swapped to page area. Use % = allocated memory/total-memory X 100% for the type of memory in question CurrUS[KB] Currently used memory at the instance MaxUse[KB] High-water mark since the SAP instance is started In Mem[KB] Con gured total memory OnDisk[KB] Con gured disc space(Virtual memory). Program etc.2 SAP Memory section explanation This section shows con gured memory/virtual memory for a list of sap memory type and their memory usage. SAP transaction SM50/SM66 is a work process monitor. Click how to run SAP SM50/SM66 transaction to know more about SAP work process and monitor. update and spool are non-dialog tasks.3 SAP mode list screen Figure 3 screen shows SAP Memory usage for every external session by every logon user who is in the instance. Jobs are executed “BGD” SAP work processes. 3. SM37 background job is a non-dialog task. Step Sequence allocation – next memory area only if memory allocated in previous steps is not enough.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Column Explanation texts Sap tasks type like dialog. Non-dialog tasks can use memory up to an amount <=Roll + Heap + Extended. Column Explanation user Sap user –same user might have more than one entries EM used Extended Memory used by a user session in KB Heap Heap memory used by a user session in KB Other columns like “I-mode G1” etc I have not found the need to use those columns for SAP memory analysis. Mode list has two sections – the upper section show current status. Update tasks are executed in SAP “UPD” work processes.sapperf. Transaction executed online by SAP user is a dialog tasks. Extended and Heap Amount Con gured the memory size for the tasks. SAP ST02 transaction and memory analysis http://www. RFC calls and online transactions are executed in dialog work processes.ca/runsapst02memorymonitor/ 7/11 . the lower section shows history information. Job. Dialog tasks are executed in SAP Dialog work process. background etc. 2. Memory type 3 possible memory types under current SAP design: Roll. The SAP screen quotas screen (see gure 2) answers the question of what is maximum memory a SAP process can use: Dialog tasks can use memory up to an amount <=Roll + Extended + Roll + Heap. SWAP and buffer invalidation is different concept.sapperf. Buffer invalidation is due to changes on buffered object which would involve transfer from database table. this could be due to a frequent changed buffered table whose buffering should be turned off. But next read on a swap buffered object would trigger system’s action to reload the swapped object from database. SWAP itself would not increase “database access”. Heap memory. you might need to review table buffering for the instance. Enough Free memory and free directory entry: this would help avoid swap.1 SAP memory analysis at instance level SAP extended memory. it would reduce swap to increase con gured memory space and/or max directory entry when free main memory is available. SAP memory analysis is to focus on following items Free memory: We should have enough free memory in Extended and Heap memory. there might be memory contention causing job/program cancellation. Maximum memory: Maximum used memory since start of instance should be lower than 80% of what con gured memory for Extended memory and Heap memory.1 SAP Buffer analysis SAP Buffer analysis is to focus on following items Hit rate: should not be lower than 98% except program buffer. You can use SAP transaction ST10 to review table buffering or you can navigate to table buffering from the main screen. If database access is high for table space buffer area and swap is low.2. Roll memory and Page memory are SAP memory space shared by all SAP work processes. Vice Versa. single record buffer and export/import buffer where low hit rate is normally considered acceptable.ca/runsapst02memorymonitor/ 8/11 . 3. less free directory and/or less free memory space. If you saw big swaps. Buffer invalidation is not re ected in swap column but it would increase “database access”. Low swaps in single record buffer and export/import buffer is not signi cant. Otherwise. Swaps: The goal is to avoid swap in all Buffer except program buffer. http://www. the maximum used memory should not exceed sum of amount con gured “in Memory” column and on disk.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Here I would focus on SAP Buffer and SAP memory. this would cause swap. SWAP is due to shortage of free buffer space/directory. this would increase “database access”.2 SAP Memory analysis 3. 3. If there is free space but there is no free directory. For SAP page memory and Roll memory. Current used memory should not exceed 80% to ensure that free memory is still available for new memory demand. 2 SAP memory analysis at individual job/user level Figure 2 screen also shows type and amount of memory which can be used by a single SAP work process and which one should be used rst (Allocation sequence).sapperf.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance It is important to online transaction performance to have enough extended memory. you can decide whether we need to tune memory usage for the programs and jobs. A SAP work process would be terminated by SAP system if there is no memory at last step of allocation. you can go to mode list screen (Figure 3 screen) to nd which program and users are consuming those memory. it would not use “Roll” and “heap” memory. a SAP background job/process would be terminated by SAP system if the job needs more memory than what is available at extended memory space due to the fact that the job needs more than what allowed by the quota or running out of extended memory. SAP work process would get memory from heap area based on SAP allocation sequence for dialog tasks. If the online process needs more memory than what is available in heap memory after it consumes available memory from extended and roll memory space. the SAP dialog process would be in a Private mode – cannot be shared with other tasks. the program/process would be terminated by system due to memory resource contention issue. Further clari cation SAP ST02 cannot monitor SAP Extended Global Memory con gured via EM/global_area_MB http://www. if an online SAP process needs less than 7M bytes memory and there is at least 7M bytes free memory from Extended Memory.ca/runsapst02memorymonitor/ 9/11 . The actual memory allocation for a SAP work process would depend on memory demand of the program and availability of memory of each type. If current usage is high for extended memory/heap memory space. Base on those information. If this is no free extended memory.2. In similar way. 3. Mother day – until May 4. reschedule the jobs/programs or we need to have more extended memory. this would impact dialog response time and RFC task due to shortage of dialog work processes. Once a Dialog is using heap memory. Dialog task can have up to 7M memory in the extended memory space. Based on gure 2. If many dialog processes are put into “private mode”. sapperf. SAP ST02 memory monitor is one of SAP resource monitoring tools together with SAP operating system monitor (ST06) . However SAP EG memory is part of SAP extended memory. SAP database monitor (DB02 or ST04) and SAP work process monitor (SM50/SM66). adjust memory quotas for individual process. SAP MEMORY QUOTAS FOR INDIVIDUAL PROCESS. SAP ST02 SCREENS EXPLANANTION. In my view. tune application job/program and/or rescheduling job/program.thanks eric JULY 30.2 I wonder “Dialog task can have up to 7M memory in the extended memory space”.It’s 700M(781. free memory and enough free sap work processes. 2013 AT 4:23 AM 3. Based on SAP buffer and memory monitoring. then a well-tuned SAP system should be healthy from SAP system performance point view.ca/runsapst02memorymonitor/ 10/11 .2. 2013 AT 9:44 AM http://www.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance parameter directly. 6 THOUGHTS ON “HOW TO RUN SAP TRANSACTION ST02 AND DO PERFORMANCE ANALYSIS IN SAP MEMORY/BUFFER AREA” lizengfeng JULY 30. navigate through ST06 Screens and understand ST06 screens 0″> SAP ST02 SAP BUFFER/MEMORY MONITOR: SAP ST02 BUFFER/MEMORY ANALYSIS. How many memory can be con gured is limited by physical memory and con gured swap space for the server. you can refer to my post how to run SAP transaction ST06 . Physical memory usage and swap space usage can be monitored via SAP transaction ST06.250kb)? Please help me. if there are free CPU power. the outcome of review can be one or several actions: increase SAP memory allocation at instance level. 2012 AT 4:46 PM I just want to tell you that I am all new to weblog and really loved you’re web page.sapperf. if this is the case.I love your writing so much! proportion we communicate more approximately maillot de foot pas cher your post on AOL? I require a specialist in this area to solve my problem. 2013 AT 4:05 PM Thanks.5/30/2016 How to run SAP transaction ST02 and do performance analysis in SAP memory/buffer area | SAP application performance Hello. You surely come with really good posts. extended memory a dialog task can have is determined by SAP memory parameter ztta/roll_extension. application program design or the way a program is executed needed to be reviewed. Most of dialog tasks should not need that much extended memory normally. Maybe that is you! Looking ahead to peer you.hu@sap-perf. 2013 AT 11:37 AM would you mind writing more posts about this subject? lista de email lista de email lista de email lista de email lista de email eric JANUARY 4.ca Duncan Owensby DECEMBER 31. What is your expectation? You can reach me via email: eric. Most likely I�m planning to bookmark your site . http://www. extended memory for a dialog task should not be more than total extended memory for all dialog tasks which is speci ed by em/initial_size_MB which is further limited by server capacity and con guration.ca/runsapst02memorymonitor/ 11/11 . Yes. maillot de foot JANUARY 5. Thank you for sharing with us your website page. it can and it dependd on your server capacity and SAP memory parameters Technically.?????????`????????�? ?????????`????????�? lista de email JANUARY 4. 2013 AT 6:56 AM hello!.
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