I am planning to micro benchmark my java code which involves several calls to local as well as remote database. I was about to use System.nanoTime() but started reading about the micro benchmarking frameworks such as jmh and caliper. Use of these frameworks is definitely recommended but from whatever (little) I read, it seems that we can benchmark only a complete method and also it allows us to do this non-invasively (w.r.t existing code) i.e., we need not litter existing code with the code/annotations of jmh/caliper.
I want to benchmark only specific pieces of code (statements) within some methods. Is it possible to do this with any of micro benchmarking frameworks? Please provide some insights into this.
I guess, calls to a DB are usually expensive enough to eliminate most of the problem with microbenchmarking. So your approach was probably fine. If you're measuring it in production, repeating the measurement many times, and don't care about a few nanoseconds, stick with System.nanoTime.
You're doing something very different from microbenchmarking like e.g. I did here. You're not trying to optimize a tiny piece of code and you don't want to eliminate external influences.
Microbenchmarking a part of a method makes no sense to me, as a method gets optimized as a whole (and possibly also inlined). It's a different level.
I don't think any framework could help, all they can do in your case is automate the work, which you don't seem to need. Note that System.nanoTime may take several hundreds cycles (which is probably fine in your case).