Web Application Performance Tuning Checklist

By Peter A. Bromberg, Ph.D.

 Peter Bromberg

 

Recently I suggested a developer meeting at our company to address performance and scalability concerns for a Web- based application we are developing. The application is hosted on a Windows 2000 server farm with shared access to a RAID-based SQL Server 2000 installation. The front end of the app is an IE 5.5 browser-based GUI that employs a lot of DHTML, XML and XSLT to render the pages. Portions of the application also access an AS400 - based host running DB2. I though it would be useful to put up a generic version of the performance tuning "hit list" that I came up with for the meeting. Most of the items you'll see in the outline that follows are self - explanatory, and almost all of the others can be found in the Microsoft documentation for the particular product involved:



Performance Tuning - Suggested Major Areas:

Operating System:

  • Tuning of RAM
  • "Application Server" settings for server boxes
  • Disabling unnecessary services
  • Hard drive speed / configuration
  • Paging file configurations i.e. where, how big, how many
  • Locations (and configuration) of IIS logs and SQL Server Transaction Logs.
  • Network throughput and TCP packet size tuning for the Intranet.

COM+:

  • Server vs Library Applications (Performance)
  • Placing congruent COM+ business objects into the same application package�
  • Resource Pooling vs. GetObjectContext() method for ASP and within COM+ VB objects
  • Application Component Grouping - the middle-tier components should be divided into time-dependent and time-independent services (i.e. MSMQ, "service" type components)
  • Look into different ways to have asynchronous (background) or scheduled (services/ MSMQ) operation of long � running queries rather than client having to wait for them to finish while trying to use the application.
  • BaseAddress Allocation � All components should have a unique DLL Base Address to avoid object creation contention at the server level
  • Correct Setting of VB Project Compile Settings to enable maximum COM+ scalability ("Unattended Execution" and "Retained in Memory")
  • Optimization at the code logic level (e.g., using the new built-in "Split", "Join" and "Replace" functions vs.� older slow "looping" hand-coded functions)
  • Additional Compile-Time optimizations can speed up components (where permissible):
    • Optimize for fast code
    • Assume no Aliasing
    • Remove array bounds checks
    • Remove Floating Point Error checks
    • Allow Unrounded floating point operations
    • Remove safe Pentium FDIV checks

Internet Information Services:

  • Use of Response.IsClientConnected to minimize overhead on long-running queries
  • COM objects are released earlier if they do not use the OnEndPage method but use ObjectContext.SetComplete instead.
  • IIS Server Settings:
    • ASPQueueConnectionTestTime
    • ASPThreadGateEnabled
    • ASPProcessorThreadMax
    • ASPScriptEngineCacheMax
    • ASPScriptFileCacheSize
    • ASPRequestQueueMax
    • ObjectCacheTTL Registry Setting (not present by default)
    • Setting of aggressive Connection Timeouts to combat network latency
    • Use of Process Throttling for certain applications
    • Using HTTP KeepAlives
  • Optimize DHTML and other page � generating code to most efficiently use the IE5.5 browser�s capabilities in the DOM / DHTML object model.
  • Making sure Debugging is turned off (locks down to single thread)
  • Turn off ASP Session State for pages / Apps that don�t use it or use a SQL Server Session Management component instead
  • Store log files on separate disks and remove nonessential information
  • Use CPU Throttling for rogue out-of-process applications.
  • Pooling of web applications with ISM Application (isolation) protection settings � (Low, Medium, High)
  • Synchronization of� IWAM_<machine> Identity with COM+ (SyncIwam.vbs)
  • Use of Terminal Services to remotely administer servers.
  • Monitoring and testing of Server Performance with WCAT ("Homer"), HTTPMonitor and Network Monitor.
  • Performance Counters and recorded results reports
  • Add <% @enablesessionstate=false %>at top of pages not using session vars.

SQL Server Performance Tuning:

  • Creation and tuning of proper indexes for all tables
  • Avoid storing of unnecessary logging information in production mode
  • Optimization of stored procedure queries for speed
  • Always use the adCmdStoredProc property in ASP stored proc execution
  • Use LookupTable object (Free �threaded)� in Application Scope to cache frequently-used data
  • If using COM+ components to access SQL Server, make sure that SetComplete or SetAbort methods are called correctly to release server resources. Make sure all connection objects are opened as late as possible, and closed as early as possible, and set to "Nothing" to release back to connection pool.
  • Recordsets should be opened explicitly and the correct "lowest resource use" properties set for the particular situation. Recordsets should be closed and extinguished to free resources as soon as possible.
  • NT Windows Fibers
  • Max Async IO
  • Default Network Packet Size for SQL Server
  • MinMemoryPerQuery Setting
  • PriorityBoost / TimeSlice / MaxWorkerThreads service settings for SQL Server on dedicated machine

�Obviously, this is not a complete list by any means. But if you are charged with performance tuning of a web - based application running on Windows 2000 and using SQL Server as the data store, this should be a good start!

 

Peter Bromberg is an independent consultant specializing in distributed .NET solutions Inc. in Orlando and a co-developer of the NullSkull.com developer website. He can be reached at info@eggheadcafe.com