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A command line tool that analyzes request logfiles (e.g. Rails, Merb, Apache) to produce a performance report.
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This is a simple command line tool to analyze request log files in various formats to produce a performance report. Its purpose is to find what actions are best candidates for optimization.

  • Analyzes log files. Currently supports: Amazon S3, Apache, Delayed::Job, Merb, Mysql, PostgreSQL, Rack, Rails and more.

  • Combines multiple files and decompresses compressed files, which comes in handy if you are using logrotate.

  • Uses several metrics, including cumulative request time, mean request time, process blockers, database and rendering time, HTTP methods and statuses, Rails action cache statistics, etc.) (Sample output:

  • Low memory footprint and reasonably fast, so it is safe to run on a production server.

  • MIT licensed

See the project wiki at for documentation and additional information.

Installation & basic usage

Install request-log-analyzer as a Ruby gem (you might need to run this command as root by prepending sudo to it):

$ gem install request-log-analyzer

To analyze a Rails log file and produce a performance report, run request-log-analyzer like this:

$ request-log-analyzer log/production.log

For more details, other file formats, and available command line options, see the project's wiki at

Benchmarking on different rubies

$ time ./bin/request-log-analyzer 40MBRailsFile.log

ruby-1.9.2-p0   15.19s user 0.95s system 99% cpu 16.143 total
ruby-1.8.7      25.21s user 1.02s system 99% cpu 26.238 total
jruby-1.5.3     32.64s user 4.84s system 99% cpu 37.629 total
rbx             46.60s user 2.71s system 108% cpu 45.324 total
macruby         75.00s user 20.10s system 110% cpu 1:26.13 total

Additional information

Request-log-analyzer was designed and built by Willem van Bergen and Bart ten Brinke.

Do you have a rails application that is not performing as it should? If you need an expert to analyze your application, feel free to contact either Willem van Bergen ( or Bart ten Brinke (

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