Something is bothering me this past week. I've been taking some stabs at reducing the maximum render time of a site, when the caches are all empty. I cache certain components and queries, but when the caches are primed the render time is under 500ms and I think that's pretty good. That worst case senario, however, is just not acceptable. Worse than a couple seconds. That isn't time that should be taken. I dug in and found a really bad pattern.
It isn't hard to make a page faster, but the default is to be as slow as possible. We have to understand this pattern. I am looking at this in relation to Django, but I have a feeling there are similar patterns other places.
The common tagging application is a good example. It makes it really easy to tag objects, count them, query by them, and build those clever little clouds. You're given lots of new wrappers for all the common tag-related queries you'd need to do. This may be a source of the problem. We've gotten into a rut of complacency with components that give us more rope than we need to hang ourselves. Abstraction hides the cost of operations.
Are we asking the really simple question: Why are we pulling when we could be pushing? With one of the most read-heavy information systems in the world, everything revolves around the needs and demands of the almighty HTTP request. A browser asks a question and then we go and figure out the answer. We are, by default, building our software around the read when we should be building around the write.
Caching is lazy. We should be pro-active. How often is a tag cloud going to change? Only when the taggings change, of course. No page request should ever generate a tag cloud. We should be building the cloud, as a static html snippet, every time the tags change. When we're actually rendering a page, we should just insert that current snippet.