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Appeon Performance Tuning Guide
Appeon Performance
Expected performance level
Automatic performance boosting
Impact of the Internet and slow networks
Impact of “heavy” client-side logic
Impact of large data transmission
Performance-Related Settings
Appeon Developer performance settings
Appeon Enterprise Manager performance settings
Timeout settings
DataWindow data caching
Multi-thread download settings
Custom Libraries download settings
Log file settings
Internet Explorer performance settings
Web and application server performance settings
SAP Sybase EAServer
JVM startup option
Configuring data sources
HTTP properties
Microsoft IIS server
Recommendations for avoiding common errors on IIS
Advanced thread settings
Database performance settings
Recommended database driver
Recommended database setting
Identifying Performance Bottlenecks
Heavy window report
Appeon Performance Analyzer
Getting Started
Enabling Appeon Performance Analyzer
Starting Appeon Performance Analyzer
Getting to know Appeon Performance Analyzer
Removing Appeon Performance Analyzer
Working with Appeon Performance Analyzer
System Configuration
Calls Analysis
Download Analysis
View Detail
Additional Functions
Testing Appeon Web applications with LoadRunner
General Limitations on Performance Testing
Testing Environment
Testing Steps
Configuring AEM
Data Preparation (for update only)
Preparing Test Cases
Recording Scripts
Modifying Scripts
Additional steps for Update operation
Parameterization of SQL statements
Playing back Script to test the correctness of scripts
Setting Scenarios
Additional steps for Update operation
Running Scenarios
Modifying the scripts of NVO
Modifying the scripts of EJB/JavaBean
Errors appear when playing back scripts with LoadRunner 8.0
The value of sessionID is null
Error message appears in script playback
Error message in Appeon Log
Failed to parameterize scripts
Out of memory error and application server shut down
Field values do not change after parameterization and playback
Runtime errors causing scenario failure
Transactions failed
Unable to connect to remote servers
Analyzing log files
Analyzing Windows application log files
Analyzing Appeon Server log files
Analyzing active transaction log
Identifying Performance Bottlenecks of Web Server and Application Server
Identifying Performance Bottlenecks of DB Server
Deadlock analysis
Identifying Performance Bottlenecks of PB application
Analyzing performance bottlenecks of PB application
Tuning: DB Server
Tuning: Excessive Server Calls
Technique #1: partitioning transactions via stored procedures
Technique #2: partitioning non-visual logic via NVOs
Technique #3: eliminating recursive Embedded SQL
Technique #4: grouping multiple server calls with Appeon Labels
Tuning: Heavy Client
Technique #1: thin-out “heavy” Windows
Technique #2: thin-out “heavy” UI logic
Manipulating the UI in loops
Triggering events repeatedly
Performing single repetitive tasks
Initializing “heavy” tabs
Using ShareData or RowsCopy/RowsMove for data synchronization
Using computed fields
Using DataWindow expressions
Using complex filters
Using RowsFocusChanging/RowsFocusChanged events
Technique #3: offload “heavy” non-visual logic
Tuning: Large Data Transmissions
Technique #1: retrieving data incrementally
For Oracle database server
For all other database servers
Technique #2: minimizing excessive number of columns

Impact of the Internet and slow networks

Although Appeon pushes the envelope to deliver unparalleled performance from standard Web technologies (e.g. XML, JavaScript, HTML, Java or C#), which are typically significantly slower than PowerBuilder, slow and latent network connections rob performance from even the best applications!

Network chatter and network-intensive code really highlight the weakness of a poor network connection. Any code that results in a HTTP request (i.e. server call) when executed multiple times sequentially has potential to create network chatter. There are mainly two categories of code that result in server calls - data access related and remote method invocations. Here are several common examples so you can familiarize yourself:

  • Embedded SQL (Select, Insert, Delete, Update, Cursor) including Dynamic SQL;

  • Invoking stored procedures or database functions;

  • DataWindow/DataStore Functions (Retrieve, Update, ReselectRow, GetFullState, SetFullState, GetChanges, SetChanges);

  • DataWindow/DataStore Events (SQLPreview);

  • Invoking a method of a server-side object, such as a PowerBuilder NVO, Java EJB, or .NET Component; or

  • Invoking a Web Service.

Each of the above statements will generate one call to the server utilizing HTTP, with exception of SQLPreview event that will generate one call for each line of code handled by the event. If any of the above statements are contained in a loop or recursive function, well depending on the number of loops, even though its just one statement it would be executed multiple times generating multiple server calls. Needless to say, loops and recursive functions are some of the most dangerous from a performance perspective.

The reason it is important to minimize server calls is because it can take 100 or even 1,000 times longer to transmit one packet of data over the Internet compared to a LAN. Imagine an event handler is triggered, for example handling an "onClick" event, whose execution will result in 80 synchronous server calls over a LAN with latency of 2 milliseconds (ms). In such scenario the slow-down attributed to network latency would be 0.16 seconds (80 x 2 ms). Now imagine this same event handler running over a WAN with latency of 300 ms. The slow-down attributed to the network latency would be a whopping 24 seconds (80 x 300 ms)! And depending on the amount of data transmitted there could be additional slow-down due the bandwidth bottlenecks.

It is imperative for the developer to be conscious that PowerBuilder applications deployed to the Web may not be running in a LAN environment, and as such there will be some degree of performance degradation. How much depends on how the code is written, but in most cases the performance degradation still falls within acceptable limits without much performance optimization.

Should you find that certain operations in your application are unacceptably slow, the good news is there are numerous things that you can do as PowerBuilder developers to ensure your PowerBuilder applications perform well in a WAN environment (e.g. Internet) or on slower networks. At a high-level, your code needs to be written such that the server calls and other performance intensive code is minimized or relocated to the middle-tier or back-end. This will be covered in more detail in the following chapters. Some changes are actually quite simple while others may require increased effort. Nonetheless, in all cases optimizing the performance of your applications in PowerBuilder is just a fraction of the effort to work with typical low-productivity Web tools such as VisualStudio.NET and Eclipse.