I am attempting to develop a cms system that will use tags to display similar content. For example, underneath the news section there will be articles, blogs, news and forum questions that share the same tags. There will be no more than 5 items in each list.
I am considering 2 options for displaying this related content and am wondering if developers with more experience than myself would recommend one over the other?
Speed is the primary goal, because we have equally maintainable ways of executing both options.
Option 1 - Output Caching RenderAction Results
For each 'similar content' section, render a child action on the corresponding controller and cache the output. This feels more in the spirit of MVC, and would be light on DB calls. But with 5 'similar content' lists, that would equal 6 full MVC cycles for each page request.
I've read that RenderAction can still be expensive, even though it has improved in the last couple of years.
Option 2 - RenderPartials with DB Queries for Each
Alternatively, for each 'similar content' section, we could query the db and use RenderPartial to display the output. Although this would require a small DB query for each section (5 items or less), I'm wondering how that would compare with the performance saved by NOT calling RenderAction.
I've frequently read how much faster RenderPartial is compared to RenderAction.
Essentially your choice boils down to which is faster: RenderAction with an already cached result or 5 DB queries?
When you look at it that way, you really are talking about one solution with no network latency and one solution with network latency (sending the query to the database and receiving a response). Any solution that removes network latency is de facto faster than an alternative with network latency.
Also, bear in mind that purists like to talk about how one thing or another is "slow" compared to some other way. Yes, child actions will always be slower than partials because child actions go through the whole routing infrastructure and then finally to the Razor template engine whereas partials just go directly to the Razor template engine. But, we're talking about highly optimized, compiled code running in memory. "Slower" is measured in milliseconds or even nanoseconds. Sure, those can add up over time, and if you did something crazy like render 50 child actions in a single view, you might see some noticeable performance loss, but this will typically not be an issue worth worrying about in 99.9999% of cases.
Just design your application in the way that makes the most sense for your application and stop worrying about a millisecond here or there.