QGrid v1.2x

Using the plug-in


Enhancing performance with the image cache

In order to speed up cell redrawing QGrid caches cell images when the user is scrolling up and down the plug-in area. Image caching also decreases the number of datafile accesses, which is highly desirable especially in client/server configurations.

To experience image caching scroll down a grid that contains several hundreds of cells: the first time you display a new part of the grid you will notice a delay while images are being transferred from the database, combined with captions and background pictures and the image cache is built. If you scroll up again the grid will be displayed instantaneously.

Keep in mind the following:

On MacOS computers

QGrid allocates image cache memory from 4D's application memory. It is a good practice to allocate an extra 10MB to make sure that QGrid will have a chance to build its image cache. This will ameliorate the performance of your application, as well as avoid potential instability under low memory conditions.

On Windows computers

Because of Windows flat memory scheme, QGrid always gets the memory it requests but this may degrade overall system performance when physical memory is not enough. Make sure your machine has enough real memory to hold all that is running concurrently.

If you have maximized grids displaying lots of pictures simultaneously, QGrid's image cache will be filled sooner. The larger the viewable grid surface is, the shorter the caching effect will last.