The current log parsing and report generation process is not particularly efficient, and that is something we'll be addressing in a future release. However, even mature analysis tools like Webalizer do require a significant amount of time to run. I suspect we'll move to a batch process in the future to best accommodate larger log files.
Note that the process of logging visitors is not a problem; it is fast and doesn't depend on the size of the log file. It's only the process of analysis that takes time and memory. You may find that increasing your memory and processing time limits in php.ini allows you to analyze bigger log files. Different releases of PHP (e.g. 4.x vs. 5.x) also behave very differently in terms of performance and memory usage with objects; in my experience, 5.x is significantly better.
Open Journal Systems Team
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