Why is using the cache tag more expensive than outputting static text?

Question

The Craft docs have a good overview of the {% cache %} tag.

The docs give a couple examples of when not to use the {% cache %} tag. In particular, they give this example:

Don’t use them to cache static text; that will be more expensive than simply outputting the text.

Can someone explain to me the logic behind this statement? How do the two scenarios play out where caching static text is slower than just outputting it?

Additionally, what if you are caching a page with several queries that includes static text? Does it follow that you'll want to cache the queries in and of themselves and let the static text remain uncached?

Answer 1

Since the {% cache %} tag solely stores its information in the database, it has a guaranteed minimum of one database call to make to see if what's inside of it has already been cached.

If you're just doing this:

{% cache %}
    Hi. I'm static text.
{% endcache %}

That's quite a bit more overhead than simply:

Hi. I'm static text.

With no real benefit.