Catalog Performance

I have a catalog that has around 250 items (so far). It has quite a few fields, including an Image field. I've setup a test Lister module and have been experimenting how enabling and disabling fields in the "View" section affect load times. I've made a simple test template that only shows the Product Name, no other fields are rendered.

I've found that despite this, just enabling or disabling fields in the "Visible Fields" section of the Lister can have dramatic effects. When enabling the Image field in particular, it caused the page load time to go from 6 seconds to over a minute if the page was not previously cached. When loading the page subsequent times, it took around 16 - 18 seconds.

Other than limiting the number of items displayed, does anyone have any tips for increasing performance?

The reason for this performance impact is, that the catalog will "render" every field selected for output despite the fact that you are not displaying it in the frontend (via echo in the template).
The impact when selecting an image field is, that the catalog has to create the thumbnails (if they do not exist yet), the resized image and all of this.

Therefore only select the fields you are actually using for output (or those you need to generate the output in terms of checkbox flags etc.).

Via the selection on "visible fields", you are telling the catalog that you need the rendered output of these fields in the Template and this rendering simply costs time.

However, depending on the amount of images the catalog has to generate, 16-18 seconds sounds rather long to me. Maybe you should upgrade your server as for my sites, the loading times of catalog pages never exceed 3-4 seconds maximum for the first impression and less than one second for subsequent impressions, where the thumbnails have already been created (when having a full gallery of images, like an image field of 80 selected images).

Could you please shed some light on the catalog configuration and pinpoint what fields exactly turn out to be the bottle neck on your side in addition to the hosting environment (like CPU, Memory, php version, mysql on localhost or remote, etc.)

Regards
Chris