What affect will enabling the response time (%D) LogFormat directive have on apache performance?
The response time is the time taken to serve a request in microseconds.
Response time can be enabled like so:
#LogFormat "%h %l %u %t \"%r\" %>s %b" # Default LogFormat
LogFormat "%h %l %u %t \"%r\" %>s %b %D" # LogFormat including response time
I have written a tool for monitoring and analysing backend script performance, apache-response-time, which requires response time data. I would like to warn potential users how enabling this directive will affect apache server performance.