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MII locking up and Java applet performance

Our MII web application is locking up intermittently. When this occurs, it must be unlocked by performing the equivalent of Ctrl-Alt-Delete. The issue is unpredictable but happens often enough to seriously frustrate users.

For reasons below I believe this is a performance problem with our Java applets, but this is difficult to prove.

Resolutions we’ve considered are listed below. Comments would be appreciated.

Symptoms of current problem:

  • When people use MII on our server farm, occasionally it will lock up. (See “system landscape” below for server farm details.)
  • This has happened more and more frequently, as more and more users have started using the server farm
  • Happens often enough to be very frustrating to users
  • Happens seldom enough that we cannot reproduce it on demand
  • We can’t identify a specific trigger within the MII web application
  • When this happens, the user can “unlock” the lock-up by triggering a process we created that kills that user’s IE and Java processes on the server farm.
  • Lest you think I am leaving you no clues whatsoever, see below for a similar previous problem we were able to resolve.

Previous problem Nov 2012: iBrowser applet function causing lock-ups

  • Symptoms:
    • We had an .irpt page in MII that periodically locked up (requiring Ctrl-Alt-Delete). It couldn't be reproduced by users that were VPN'ed into our system, but users on site could lock up MII by clicking on a certain button frequently.
    • When it locked up, you could unlock it by killing either the user's IE process. You could also unlock it by just killing java.exe. So clearly a Java issue.
  • Cause: Eventually this was traced to an iBrowser applet function that got called when you clicked on a button.
    • My coworker tells me this was linked to a bug with that applet function, though I haven't confirmed this.
  • Resolution: We removed our usage of that applet function.
  • Similarity to current issue: similar, but this was happening much more frequently than our current issue, it could be reproduced, and we were able to isolate the cause.

Possible resolutions we’ve considered:

  • Replace some of our applets with AJAX calls (starting with the most frequently-used and easily-replaced applets)
  • Buy more servers for the server farm

Our system landscape:

  • Our client computers have the following profile:
    • Almost all Windows 7
    • IE 8 is the only browser used
    • Java version 6 Update 18
    • Some use their locally installed IE, but most do not. Most use the server farm’s instance of IE to view MII.
  • Server farm
    • Most users get to MII not by opening their local IE, but by executing a local .RDP file to open up a remote instance of IE which runs as a published application on the server farm
    • The published application is done via Remote Desktop technology. (It looks similar to a local IE instance; it does not look like a full-fledged Remote Desktop Connection with a visible desktop, but the technology is basically the same.)
      Windows Server 2008 R2
    • IE 8 is the only browser used
    • Java version 6 Update 18
    • 7 servers are in the farm
    • We bought this server farm specifically for MII to comply with our company’s Java update policies and to address past issues we were having
    • Traffic is load-balanced via Remote Desktop Connection Broker
    • Looks like we currently have up to 15 users per server, but we are looking to expand this.
  • MII:
    • Version 12.2.4
    • Running on a Linux server
  • PCo:
    • Version 2.3 (2.302.1631.1246)
    • Running on a Windows 2008 R2 server
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    author's profile photo Former Member
    Former Member
    Posted on Dec 03, 2013 at 07:02 PM

    Hi Greg,

    without having red everything carefully, this reminds me of a similar behaviour. I see the root cause in the fact that the default settings of MII (Netweaver) are such that it is not scalable at all. I have asked SAP to integrate the settings tested by Salvatore Castro as default settings in MII but it was neglected by SAP. So, please try to configure the settings of MII such that it is capable of normal user load.

    Please see the following document to proceed with the settings:

    http://scn.sap.com/docs/DOC-1834

    Some of the settings are different on 12.2. Please see my add-on paper to the document above below.

    To remind everyone: These settings are an absolute must for every MII deployment!

    And I ask SAP again: Please make this settings default for every MII installation!

    Netweaver MII Performance Settings

    Table of Contents

    • 1 Netweaver / MII Performance Settings
      • 1.1 Motivation
      • 1.2 Parameters to change with "ConfigTool"
      • 1.3 Additional parameter to place in NW profile

    1 Netweaver / MII Performance Settings

    1.1 Motivation

    The settings mentioned in this howto are necessary for a standard MII production environment. This is because Netweaver's default settings permit only a few amount of parallel HTTP requests. If the number of parallel requests exeeds 6 (really parallel with a delay of a couple of ms) blockage appears on client side delaying page / data reloads massively (30s - 60s and more is common). Parallel requests of this kind can happen easily from different browser windows or data reload of multiple graphics on a HTML page which load there data independently. The settings described here increase all necessary thread pool, connection, requests and queue limits to mitigate that problem.

    1.2 Parameters to change with "ConfigTool"

    The parameters listed here are related to NW version 7.1 Patch 6 and MII 12.2.2.5. Parameters and settings described here are an excerpt from document The Performance of SAP MII on Intel Xeon Hardware Analysis Summary. Parameters have been adapted to NW 7.1 Patch 6. Some of them are not needed anymore because they are built dynamically and some of them have not been set because they are configured by default installation.

    Start ConfigTool with running a Windows command window as Administrator. CD into directory and start configtool.bat. Full qualified path:

    <drive>:/usr/sap/<SID>/JXX/j2ee/configtool/configtool.bat 

    The following table lists the parameters to change to the values given in column "Custom Value". "Path (Instance)" specifies the path of the parameter in the tree view of the config tool.

    Path (Instance) Parameter Default Custom Value Remarks Managers -> ApplicationThreadManager MaxThreadCount 100 1000 Managers -> ApplicationThreadManager PercentageOfParallelismAllowed 30 50 Managers -> ThreadManager MaxThreadCount 100 1000 Services -> cross maxServiceThreads 5 5 Services -> dbpool sysDS.initialConnections 1 10 Services -> dbpool sysDS.maximumConnections 20 max (($link{../../../kernel/ApplicationThread/properties#MaxThreadCount} min (round(200/$link{${SYSTEM_INFO}#NumberOfNodes})))-10) 20 max (($link{../../../kernel/ApplicationThread/properties#MaxThreadCount} min (round(200/$link{${SYSTEM_INFO}#NumberOfNodes})))-10) Dynamically calculated from Application MaxThreadCount. Services -> http FCAServerThreadCount 5 50 Services -> IIOP parallelRequests 10 1000 Services -> IIOP requestQueueSize 100 1000 Services -> jmsconnector maxConnections 100 500 Services -> jmx NotificationQueueMaxThreads 3 30 Services -> jmx NotificationQueueThreadThreshold 30 100 Services -> p4 parallelRequests 10 1000 Services -> p4 requestQueueSize 100 1000 Services -> security sessions_size 200 1000 Services -> servlet_jsp ProductionMode true true Value True is already defaulted.

    Detailed information about each of these parameters can be found in the online: NetWeaver Help Documentation

    1.3 Additional parameter to place in NW profile

    The following parameters has to be added to the Netweaver profile. Path to profile:

    <drive>:\usr\sap\<SID>\SYS\profile\<SID>_<JXX>_<Server> 

    Note: The file has no extension.
    This is a plain text file so you simply need to open it in any text editor; before modifying this file be sure to first backup this file. The following parameters were modified/added to the profile:

    #----------------------------------------------------------------------- # Number of usable threads #----------------------------------------------------------------------- icm/min_threads = 100 icm/max_threads = 1000 #----------------------------------------------------------------------- # Increase the size of the MPI memory area #----------------------------------------------------------------------- mpi/total_size_MB = 500 #----------------------------------------------------------------------- # Number of maximum connections, length of the wait queue #----------------------------------------------------------------------- icm/max_conn = 2500 icm/req_queue_len = 2500 #----------------------------------------------------------------------- 

    These parameters are referenced in the SAP NetWeaver CE Help documentation on the ICM for systems with an anticipated “High Load” as described here: http://help.sap.com/saphelp_nwce10/helpdata/en/56/2e453cabf4ef6fe10000000a114084/content.htm

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    • As for upgrading to HTML5 there is a completely different way that you define objects on the page as per the HTML 5 spec. Everything is managed on the page as a <div> object that you define objects for using JavaScript and tell them to display in the various <div> objects that you've defined. In MII 15.0 there is also a drag and drop builder environment that will allow you to quickly define a web page and also see how the objects are defined. This will greatly improve your ability to construct pages and also migrate over to HTML5.

      Sam

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