Understanding Static and dynamic Content
All data has a life span; the length of this span is referred to as the persistence of the data. By convention, more persistent data is referred to as static content; less persistent data is called dynamic content. In the real world, however, data persistence exists on a continuum, and ‘static’ or ‘dynamic’ designations are more or less arbitrary. Data that is extremely static (the text of a book, for example) might be called inert, and extremely dynamic data (the price of pork bellies in a futures market) might be called volatile.
The data persistence continuum, then, is more complex than a simple binary choice between ‘static’ and ‘dynamic.’ For the purposes of caching, however, these designations turn out to have some practical utility. Static content is data that does not, in general, change with each successive display of a web page. Dynamic content does. That’s a distinction that an information technology professional can work with.
The beauty of Warp Solutions technology is that it doesn’t really matter – both static and dynamic content can be cached. In fact, virtually any kind of data can be cached, regardless of its persistence. The choice, then, is no longer whether it is possible to cache dynamic or highly volatile data, but whether it makes practical sense to do so.
Persistence, Popularity, and Population
Highly persistent data is a good candidate for caching, because the likelihood of the need for a refresh, and therefore the efficiency of the cache, is low. Highly volatile data is a poor candidate for the same reasons. Why, then, would an organization want to cache dynamic data? The answer is that persistence is not the only factor to consider. Another factor is popularity. Popularity is a measure of the likelihood that data will be requested, and it is influenced by several factors.
Visibility
First let’s consider data popularity from the point of view of the audience. From this point of view, one important factor is the location or visibility of the data. Data on the home page of a web site, for example, is more likely to be requested than data on a page four levels deep. The front page of a newspaper is read more frequently than page 27. The data on your computer screen is more popular than your prized first pressing of the Beatle’s White album (at least in this context). Location is clearly important, which means that an organization can directly influence the popularity of data, and therefore, it’s suitability for caching by simply changing its location.
Inherent Popularity
Data also has inherent popularity with respect to its audience; the 5 vowels are more popular than the 21 consonants, for example, because they each occur more frequently in English words than any consonant does. Humans tend to prefer symmetry over asymmetry. Structure is preferable to chaos. Nobody likes lawyers. Inherent popularity is more difficult for an organization to influence; efforts to do so are normally grouped under the rubric of ‘Sales and Marketing.’
Population Size
Now let’s consider popularity from the point of view of the data itself. This is a much more pedestrian viewpoint; popularity is simply a measure of volume – the frequency with which the data is requested. And request volume is most heavily influenced by the size of the client population.
Consider: highly popular data within a small population will be requested frequently. Moderately popular data within an average-sized population will also be requested frequently. Even data that is comparatively unpopular within a huge population will be requested frequently. Organizations that serve a large audience, therefore, are likely to benefit from caching even ‘unpopular’ data, because the size of the population offsets the unpopularity of the data itself.
Caching Benefits
Clearly, then, in assessing the value of caching technology, an organization must consider notions of persistence, popularity, and population as applied to their web application infrastructure. Data exhibiting strength in any one of these areas must be considered as a good candidate for caching; strength in more than one area makes the decision obvious.
It is interesting to note that, when considered in a larger business context, these same characteristics – persistence, popularity, and population – can be used to influence and measure the overall success and fiscal trajectory of the business itself. In other words, the more successful your business is, the more likely it will benefit from caching technology. For medium and large-sized businesses, caching is rapidly becoming an absolute necessity for an efficient, cost-effective web application infrastructure.
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