Using apachebench (ab) with Drupal 7 to load test site with authenticated users
This post is more than 10 years old. I do not delete posts, because even old information is still useful, but please know that some material on this page may be outdated or incorrect. Thanks!
apachebench is an excellent performance and load-testing tool for any website, and Drupal-based sites are no exception. A lot of Drupal sites, though, need to be measured not only under heavy anonymous traffic load (users who aren't logged in), but also under heavy authenticated-user load.
Drupal.org has some good tips for ab testing, but the details for using ab's '-C' option (notice the capital C... C is for Cookie) are lacking. Basically, if you pass the -C option with a valid session ID/cookie, Drupal will send ab the page as if ab were authenticated.
Instead of constantly going into the database and looking up session IDs and such nonsense, I have a simple script, which is quite revised from the 2008-era script originally from 2bits that worked with Drupal 5, which will give you the proper ab commands for stress-testing your Drupal site under authenticated user load. Simply copy the attached script (source pasted below) to your site's docroot, and run the command from the command line as follows:
# [PATH_TO_SCRIPT] [HTTP_HOST] [URL_TO_TEST] [#_SESSIONS] [#_REQUESTS]
$ /path/to/drupal/root/ab-testing-cli.php www.example.com http://www.example.com/node/1 2 10
You'll get back the command to paste into the cli in order to test the URL you provided as an authenticated user. (Note: The sessions table needs to be populated for this to work, so someone (or a few someones) will need to have logged in during the past few hours/days for this to work correctly).
Here's the full code (file attached to bottom of post):
<?php
/**
* @file
*
* Script to generate ab tests for logged in users using sessions from database.
* This script is based on an older script by 2bits for load testing Drupal 5,
* located at: http://goo.gl/4pfku
*
* Place this script into the webroot of your Drupal site.
*
* Usage (from command line):
* # [PATH_TO_SCRIPT] [HTTP_HOST] [URL_TO_TEST] [#_SESSIONS] [#_REQUESTS]
* $ php /path/to/drupal/root/ab-testing-cli.php example.com http://www.example.com/ 2 200
*
* After the script runs, it will output a list of commands for you to use to
* test your website as a logged-in user.
*/
// Set the variable below to your Drupal root (on the server).
$drupal_root = '/path/to/drupal/root/';
// If arguments not supplied properly, warn user.
if ($argc != 5) {
$prog = basename($argv[0]);
print "Usage: $prog host url concurrency num_requests\n";
exit(1);
}
// Get the arguments for ab.
$url = $argv[2];
$number_concurrency = $argv[3];
$number_requests = $argv[4];
// Set this directory to your drupal root directory.
chdir($drupal_root);
// Set up required variables to help Drupal bootstrap the correct site.
$_SERVER['HTTP_HOST'] = $argv[1];
$_SERVER['PHP_SELF'] = basename(__file__);
$_SERVER['REMOTE_ADDR'] = '127.0.0.1';
define('DRUPAL_ROOT', getcwd());
// Boostrap Drupal.
require_once('./includes/bootstrap.inc');
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
// Get as many sessions as the user calls for.
$results = db_query_range("SELECT sid FROM {sessions} WHERE uid > 1", 0, $number_concurrency)->fetchAll();
// Loop through the results and print the proper ab command for each session.
foreach ($results as $result) {
$cookie = session_name() . '=' . $result->sid;
print "ab -c 1 -n $number_requests -C $cookie $url\n";
}
?>
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