I would suggest that if a change were to be made it should follow the design
Log4j 2 uses and separate the configuration from the Logger instances. The
hierarchy in the configuration is likely to be much smaller than it is in the
Logger instances.
Ralph
> On Apr 1, 2020, at 10:06 AM, Robert Middleton <osfan6...@gmail.com> wrote:
>
> Note: I wasn't involved with the design of this at all, but some thoughts:
>
> Likely the reason this was done is because that's how log4j worked -
> the classes that you see in log4cxx map closely to log4j(1) classes.
> One of the problems involved with storing the level directly in the
> logger would be actually traversing the log tree to find the correct
> level to set would be prone to error, especially if you're changing
> the levels at runtime. It's simpler and less likely to cause errors
> if you simply check whenever you log a message.
>
> With performance as well, the thing to recognize about logging(and
> really outputting data from an application in general) is that writing
> is sloooooooow. For instance, here's a simple C program you can try:
>
> #include <stdio.h>
>
> int main( int argc, char** argv ){
> for( int x = 0; x < 1000000; x++ ){
> printf( "hi this is a line\n" );
> }
> }
>
> When running on my system, this takes ~2.2 seconds to run, printing to
> stdout. If I instead output the data to /dev/null, it takes between
> .02 and .05 seconds. Sending it to a file about doubles this time to
> about .04 - .08 seconds, so still slower than discarding the data but
> several times faster than writing to stdout.
>
> Taking all of this together, it's very likely that storing the log
> level directly in the logger wouldn't have any appreciable difference
> in efficiency, unless you're trying to log thousands of statements per
> second. There's probably some way this could be improved, but unless
> you actually profile and can point to a specific spot in the code
> where a lot of time is being spent, it's probably not worth it to
> change.
>
> -Robert Middleton
>
> On Tue, Mar 31, 2020 at 3:04 PM Norman Goldstein <norm...@telus.net> wrote:
>>
>> I very much appreciate the great description of how to use log4cxx. My
>> question is about a design choice that affects performance (paragraph 2
>> in https://logging.apache.org/log4cxx/latest_stable/usage.html ). A
>> hierarchical approach for logging levels makes sense. However, each
>> run-time check of the level involves a walk of the logger hierarchy.
>> Why not do this walk when assigning levels, so that the walk does not
>> need to be done at each call to log i.e. each logger stores its logging
>> level, directly?
>
