In the following PR, there are related discussions. https://github.com/apache/spark/pull/332
------------------ Original ------------------ From: "Marcelo Vanzin";<van...@cloudera.com>; Date: Fri, Apr 11, 2014 08:16 AM To: "dev"<dev@spark.apache.org>; Subject: RFC: varargs in Logging.scala? Hey there, While going through the try to get the hang of things, I've noticed several different styles of logging. They all have some downside (readability being one of them in certain cases), but all of the suffer from the fact that the log message needs to be built even though it might not be used. I spent some time trying to add varargs support to Logging.scala (also to learn more about Scala itself), and came up with this: https://github.com/vanzin/spark/commit/a15c284d4aac3d645b13c0ef157787ba014840e4 The change may look large, but the only interesting changes are in Logging.scala, I promise. What do you guys think of this approach? It should, at worst, be just as fast (or slow) as before for the majority of cases (i.e., any case where variables were used in the log message). Personally, I think it reads better. It might be possible to have something similar using string interpolation, but I'm not familiar enough with Scala yet to try my hand at that. Also, I believe that would still require some kind of formatting when you want to do calculations (e.g. turn a variable holding milliseconds into seconds in the log message). If people like it, I'll submit a proper pull request. I've run a few things using this code, and also the tests (which caught a few type mismatches in the format strings), and everything looks ok so far. -- Marcelo .
