Danny van Kooten

Basic profiler for WordPress Plugins. Benchmarks any given plugin by testing response times with and without the plugin activated.
<blockquote>
Plugin Profiler is on GitHub.
Bug reports (and pull requests) are welcomed on the <a href="https://github.com/dannyvankooten/wp-plugin-profiler" rel="nofollow ugc">Plugin Profiler GitHub repository</a>.
Please note that GitHub is not a support forum.
</blockquote>
<h4>Profiling a plugin</h4>
This plugin measures response times of any URL on your website in the following ways.
<ul>
<li>No plugins activated</li>
<li>Only the selected plugin(s) activated</li>
<li>All but the selected plugin(s) activated</li>
<li>All plugins activated</li>
</ul>
It then plots the response times in a chart and calculates the average response time time difference.
While this way of profiling a plugin is very low-tech it can be interesting to measure the impact of a plugin on your site’s response time. 
Please note that this way of benchmarking leaves a lot of factors out – like additional HTTP requests caused by a plugin, etc..
<h4>Installing Plugin Profiler</h4>
Since this plugin needs to filter out which plugins are activated for the profiling requests, it needs to be installed as a must-use plugin so it’s loaded early.
Have a look at the <a href="https://wordpress.org/plugins/plugin-profiler/installation/">installation instructions</a> for details.
More information
<ul>
<li>Developers; follow or contribute to the <a href="https://github.com/dannyvankooten/wp-plugin-profiler" rel="nofollow ugc">Plugin Profiler plugin on GitHub</a></li>
<li>Other <a href="https://dannyvankooten.com/wordpress-plugins/#utm_source=wp-plugin-repo&utm_medium=link&utm_campaign=more-info-link" rel="nofollow ugc">WordPress plugins</a> by <a href="https://dannyvankooten.com#utm_source=wp-plugin-repo&utm_medium=link&utm_campaign=more-info-link" rel="nofollow ugc">Danny van Kooten</a></li>
<li><a href="https://twitter.com/dannyvankooten" rel="nofollow ugc">@DannyvanKooten</a> on Twitter</li>
</ul>

Plugin Profiler

The plugin is currently working, and showing the load time of all plugins, no plugins, all but one plugin you specify, and that one plugin only. Pretty good for showing clients how much their plugins are slowing down their site. I like this plugin better than the p3 profiler.

WARNING: Copying and pasting the profiler.php file from the installation instructions will cause a white screen of death. You need to replace the quotes with normal quotes.

Works with WP 4.9

Basic plugin profiler. Benchmarks response times with and without a given plugin activated.

tombenner

MySQL Profiler displays debugging information about SQL queries to admin WordPress users. For each query, the profiler displays the time, syntax-highlighted SQL, and a trace of the functions (as well as the file and line number that the functions were called from) that were called.
The list can be sorted by any of its columns, so you can, for example:
<ul>
<li>Order the list by ID to see the chronological order of the queries</li>
<li>Order the list by time to see the slowest queries</li>
<li>Order the list by query to group the queries by type (SELECT, UPDATE, etc)</li>
<li>Order the list by trace to group the queries by similar origins</li>
</ul>
The list can also filtered by typing in the search box, so you can, for example:
<ul>
<li>View all queries that use the wp_posts table</li>
<li>View all queries that are related to the use of a function in taxonomy.php</li>
<li>View all queries that are related to the use of a specific function or class</li>
<li>View all queries that call a specific MySQL function</li>
</ul>
To turn off syntax highlighting, put the following in wp-config.php:
<pre><code>define('MP_HIGHLIGHT_SYNTAX', false);
</code></pre>
To omit the file and line number from the function trace and display the functions as a comma-separated list (to save vertical space), define the following in wp-config.php:
<pre><code>define('MP_DISPLAY_FILES', false);
</code></pre>
This plugin was loosely based on <a href="http://bueltge.de/" rel="nofollow ugc">Frank Bueltge</a>‘s <a href="https://wordpress.org/extend/plugins/debug-queries/" rel="ugc">Debug Queries</a> plugin, so a hearty thanks to him for the development of that.
If you’d like to grab development releases, see what new features are being added, or browse the source code please visit/follow the <a href="http://github.com/tombenner/mysql-profiler" rel="nofollow ugc">GitHub repo</a>.

MySQL Profiler

Displays a list of each page's SQL queries and the functions calling them that can be searched and sorted by time, type, etc.

Plugin Profiler vs MySQL Profiler