Ever since I finally got to Mojave, my Engine.log file is consumed by 'Running application query took a while'; the PIDs are almost always root processes with seemingly no relation to any recent KM action; indeed, they just endlessly litter the log file while inactive, eventually purging pertinent errors or intentional log messages. I've scripted a log-scrubber, but if this bug is macOS, then KM should include a switch to 'ignore' these entries, and scrub them for me.
You are not the first to complain, and I believe Peter has taken steps to reduce some of it, where it is within his control.
If you want your own separate log file for "your" error msgs rather than KM engine ones, please try
I have to agree that there are, from my perspective, a lot of KM log entries that are entirely unnecessary. There a number logs in which many entries are repeated within a second -- all dups. I have previously requested that these type of logs be stopped, but so far they continue.
The main thing is that there is not a need to review the KM Engine log unless you have, or suspect you have, some time of KM problem, or Macro Action failure. Particularly when you have a Macro failure that gives you a brief, incomplete Notification, you need more information, and the log is the place to go.
So, to deal with all of the noise in the log, to find only the needed log entries, I wrote this macro:
I have a lot of very complex and lengthy macros dealing with apps that are not scriptable; and they often are running simultaneously; being able to look at the entirety of the engine.log, which includes much of my own intentional logging, remains necessary. I just scrub it with a shell script when no macros are running -- by applet, via another macro, of course.
I also log via shell to specific app/macro logs as it is, and I have a launch daemon watch the engine.log file, and cat/tail out anything relevant to a given macro, as well as tossing a record of any KM errors off to Growl for better-looking, more-useful alerts.
Still sad direct Growl support was needlessly deprecated; it still works just fine.