Logging the elapse time in the web server access log can be very useful for statistics and problem solving. I usually throw it in at the end of the log line (that’s generally compatible with existing log-analysis tools like awstats), and on a keyword=value format so that it’s easy to grep out. There is a small performance cost, though.
The elapse time includes everything - when filtering out log lines with high elapse-time you may typically find mobile clients downloadi ... [continue reading]