Recently I did a complete redesign in a store. As part of the redesign, I added a hierarchical, DHTML menu navigation bar to the site. In a typical setup, such a navigation bar works like this: use WITH-OBJECT :index to reference the home page, then cycle through the contents field, create a menu label for each page you find there, and for any such page, create a sub-menu if the page also has contents.
If you didn't know until now, whenever you reference another object in RTML, such as using WITH-OBJECT or FOR-EACH-OBJECT, such a reference causes a disk lookup on the server. This is what we call an "expensive" operator; it is expensive in terms of processing power and time, so a navigation bar in general, and a hierarchical navigation bar in particular is an "expensive" template.
In the store I was working in, they had over 4,000 pages, and of course, each of those pages had the navigation bar on them. So not surprisingly, the time it took to publish this site went from a couple of minutes to 3-4 hours!
ONCE to the rescue
There are many ways to write good, efficient, and bad inefficient RTML code, but regarding of your coding style, there is one operator you should consider every time you write a piece of code that won't change from page to page, and it is the ONCE operator.
Once takes one parameter, which can be either :page or :publish. What it means is that whatever you paste within ONCE will be evaluated only once per page or per publish. Now, per page is not that interesting (I think at least, I haven't really found any use for that,) but per publish is great.
When you use ONCE :publish, the expressions pasted inside it are evaluated only once during publishing. So how can you speed up your navigation bar? The immediate idea is to simply paste your original navigation code inside a ONCE :publish. Ok, try it, and you'll be quite surprised: your navigation bar will appear only on a single page, the first one that was generated during your publish. Not exactly what you want, but if you think about what ONCE does, it does make sense: you asked it to generate your navigation bar once per publish. To get the speed benefits of ONCE :publish and also end up with a navigation bar on every page, do the following small variation:
Now this will do the trick nicely! We still generate the navigation bar once per publish, but now the result is saved (GRABbed) and output on each page!
With this simple trick, my store's publish time went back to about 5-10 minutes.
I use this trick all the time for pieces of the page that doesn't have to change throughout the site. It works nicely for banners, footers, random testimonials, etc. You can use the above code snippet as a boiler plate, just put the code that needs to be evaluated once inside the GRAB operator and you'll be all set. Be careful though, don't do this to code that changes from page to page (for example, you cannot use this trick if your navigation bar changes based on which main category you are in.)
Editor still slow?
Ok, you've tried it, publish time is great, but your editor is slow. Chances are you have some inefficient RTML code in your templates, and if that's the case, ONCE will not save you anything there. Why? Because when you are in the editor, you are essentially publishing each page every time you view a page! Not the entire store (of course), but viewing any page in the editor is a "mini publish" of that page. So if you take my DHTML menu example above, that menu needs to be re-generated in the editor every time you view a page. One way to speed up the editor is to turn off slow pieces of code while in the editor. For example, you can program your template so that it does not show a navigation bar while in the editor (in the editor, you can still navigate in other means, like a bottom of page text navigation, breadcrumbs, or clicking the "Contents" button.) This is, though, a different tip for a different post!
If you didn't know until now, whenever you reference another object in RTML, such as using WITH-OBJECT or FOR-EACH-OBJECT, such a reference causes a disk lookup on the server. This is what we call an "expensive" operator; it is expensive in terms of processing power and time, so a navigation bar in general, and a hierarchical navigation bar in particular is an "expensive" template.
In the store I was working in, they had over 4,000 pages, and of course, each of those pages had the navigation bar on them. So not surprisingly, the time it took to publish this site went from a couple of minutes to 3-4 hours!
ONCE to the rescue
There are many ways to write good, efficient, and bad inefficient RTML code, but regarding of your coding style, there is one operator you should consider every time you write a piece of code that won't change from page to page, and it is the ONCE operator.
Once takes one parameter, which can be either :page or :publish. What it means is that whatever you paste within ONCE will be evaluated only once per page or per publish. Now, per page is not that interesting (I think at least, I haven't really found any use for that,) but per publish is great.
When you use ONCE :publish, the expressions pasted inside it are evaluated only once during publishing. So how can you speed up your navigation bar? The immediate idea is to simply paste your original navigation code inside a ONCE :publish. Ok, try it, and you'll be quite surprised: your navigation bar will appear only on a single page, the first one that was generated during your publish. Not exactly what you want, but if you think about what ONCE does, it does make sense: you asked it to generate your navigation bar once per publish. To get the speed benefits of ONCE :publish and also end up with a navigation bar on every page, do the following small variation:
TEXT ONCE :publish
GRAB
... generate your navigation bar here ...
Now this will do the trick nicely! We still generate the navigation bar once per publish, but now the result is saved (GRABbed) and output on each page!
With this simple trick, my store's publish time went back to about 5-10 minutes.
I use this trick all the time for pieces of the page that doesn't have to change throughout the site. It works nicely for banners, footers, random testimonials, etc. You can use the above code snippet as a boiler plate, just put the code that needs to be evaluated once inside the GRAB operator and you'll be all set. Be careful though, don't do this to code that changes from page to page (for example, you cannot use this trick if your navigation bar changes based on which main category you are in.)
Editor still slow?
Ok, you've tried it, publish time is great, but your editor is slow. Chances are you have some inefficient RTML code in your templates, and if that's the case, ONCE will not save you anything there. Why? Because when you are in the editor, you are essentially publishing each page every time you view a page! Not the entire store (of course), but viewing any page in the editor is a "mini publish" of that page. So if you take my DHTML menu example above, that menu needs to be re-generated in the editor every time you view a page. One way to speed up the editor is to turn off slow pieces of code while in the editor. For example, you can program your template so that it does not show a navigation bar while in the editor (in the editor, you can still navigate in other means, like a bottom of page text navigation, breadcrumbs, or clicking the "Contents" button.) This is, though, a different tip for a different post!
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