When you first open a Window there are two types of files downloaded. The first type is the HTML and JavaScript files ("Web files") that contain the UI and UI logic of the application Window. The second type is data files that contain the result set, for example for a DataWindow retrieve. The time to download these files is affected by two factors: 1) the network connection and 2) the size of the files to be downloaded.
The Web files do not impact performance because of their small size and the enhanced ability of the browser to "cache" them. The Web files for a given PowerBuilder Window are typically between 25-75 KB. Because these Web files are static in nature, once a given application Window has been opened, the Web files will be cached on the Client computer. As such, once these Web files are cached, their impact on performance is essentially non-existent.
Under most circumstances, these Web files are not re-downloaded when the Window is reopened. The only exceptions are if 1) the temporary Internet files folder has been emptied or 2) the application has been updated and redeployed to the server. If the latter has happened, Web files for only those Windows that have been modified will be automatically downloaded from the Web server.
Only the data files containing the result sets may or may not be cached (depending on whether you have enabled DataWindow caching). A result set of 50 records would typically result in a 12 KB data file. Every 5 records would typically add another 1.2 KB to the data file size. So, for example, a 500-record result set would typically correspond to a 120 KB data file. If DataWindow caching is not enabled, the data files corresponding with such DataWindows will be downloaded from the server each time a DataWindow retrieve is invoked.
The good news is that Appeon has built-in 10X data compression for DataWindow result set to essentially eliminate the time spent downloading these data files. The same 500-record result set that would normally correspond to a 120 KB data file would only result in the download of a 12 KB data file from the server. This compression feature makes even the largest of result sets quick to transfer.
In conclusion, due to Web file caching feature of the Web browser, Appeon's built-in DataWindow caching technology and 10X data compression technology, generally speaking neither the Web files nor data files should have any noticeable impact on the performance of your Web application.
