Artberri

WP XHProf Profiler plugin is an easy way to profile your plugins and themes when you are coding or debugging. To get it done it uses XHProf, a PHP profiler made by the Facebook Dev Team (you must install it before activating the plugin).
<h4>Usage</h4>
By default the profiling is disabled, activate <code>WP_DEBUG</code> on your <code>wp-config.php</code> to enable it. After doing it, all your wordpress pages will have a link at bottom with the profiling data.
<h4>¿What is XHProf?</h4>
From <a href="" title="From PHP documentation" rel="nofollow ugc">http://www.php.net/manual/en/intro.xhprof.php</a>
XHProf is a light-weight hierarchical and instrumentation based profiler. During the data collection phase, it keeps track of call counts and inclusive metrics for arcs in the dynamic callgraph of a program. It computes exclusive metrics in the reporting/post processing phase, such as wall (elapsed) time, CPU time and memory usage. A functions profile can be broken down by callers or callees. XHProf handles recursive functions by detecting cycles in the callgraph at data collection time itself and avoiding the cycles by giving unique depth qualified names for the recursive invocations.
XHProf includes a simple HTML based user interface (written in PHP). The browser based UI for viewing profiler results makes it easy to view results or to share results with peers. A callgraph image view is also supported.
XHProf reports can often be helpful in understanding the structure of the code being executed. The hierarchical nature of the reports can be used to determine, for example, what chain of calls led to a particular function getting called.
XHProf supports ability to compare two runs (a.k.a. “diff” reports) or aggregate data from multiple runs. Diff and aggregate reports, much like single run reports, offer “flat” as well as “hierarchical” views of the profile.
Additional documentation can be found via the xhprof website » [http://pecl.php.net/package/xhprof]
<h4>Support</h4>
Comments, questions, feature requests and bug reports are welcome: <a href="http://www.berriart.com/en/xhprof-profiler/" title="XHProf Profiler" rel="nofollow ugc">http://www.berriart.com/en/xhprof-profiler/</a>

WP XHProf Profiler

Adds PHP profiling support to your Wordpress using Facebook's XHProf Profiler.

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.

WP XHProf Profiler vs MySQL Profiler