Konstantin Kovshenin

This plugin lists the top 100 slowest actions and filters during a page request in WordPress. It helps you figure out performance bottlenecks in themes and plugins.
Requires <a href="https://wordpress.org/plugins/debug-bar/" title="Debug Bar" rel="ugc">Debug Bar</a>.
Current limitations:
<ul>
<li>Does not time nested actions and filters due to a core bug</li>
<li>Does not time actions and filters before plugins_loaded or muplugins_loaded if placed in mu-plugins</li>
<li>Does not time actions and callbacks after wp_footer at priority 1000</li>
</ul>

Debug Bar Slow Actions

many thanks to author. Excellent plugin!



MUST-HAVE for every developer.

Great!

This plugin is essential for plugin development! It also works with the Query Monitor plugin.

Indispensable!

Easily find out which actions and filters are the slowest during a page load.

Modern Tribe, Inc.

Jonathan Brinley

Peter Chester

You can use this plugin to manually log data or to capture logging on WordPress actions. You can capture load time, memory, backrace, data dumps, urls, and server IPs.
This is designed to either be managed using wp-config.php and logging OR using the admin and debugbar plugin ( https://wordpress.org/extend/plugins/debug-bar/ ). Most of the following documentation applies equally to the settings panel or the wp-config.php vars. Either one works fine. The only exception is the DEBUG_LOG configuration which is only supported as a wp-config var.
Firstly, you can manually log things using the following function:
<pre><code>do_action( 'log', $message, $group, $data );
</code></pre>
The $group allows you to selectively output logging based on groups of log messages. The $message is the string you want to see in the log. $data is an optional parameter for the data that you want to display in the log (objects, arrays, or any other sort of data really).
To render messages to the log, you must configure wp-config.php as follows:
Run debug on only these groups. Use ‘ALL’ to debug everything. The group ‘ACTIONS’ is reserved for WordPress actions.
<pre><code>define( 'DEBUG_GROUPS', 'ACTIONS,default,myspecialgroup' );
</code></pre>
Display these outputs in the log for each log message.
<pre><code>define( 'DEBUG_PARAMS', 'time,timedelta,memory,memorydelta,data,backtrace,url,server' );
</code></pre>
WordPress actions that you wish to log.
<pre><code>define( 'DEBUG_ACTIONS', 'wp_head,switch_theme,wp_footer' );
</code></pre>
Optional restriction by URL (useful on MU installs).
<pre><code>define( 'DEBUG_URLS', 'myurl.com' );
</code></pre>
Minimum time in milliseconds required to register a log entry as being slow. Default 0 for no minumum.
<pre><code>define( 'DEBUG_MIN_TIME', 500 );
</code></pre>
Minimum memory in killobytes required to register a log entry as being heavy. Default 0 for no minumum.
<pre><code>define( 'DEBUG_MIN_MEM', 1024 );
</code></pre>
Path to log file or set to TRUE to use php error log. Default FALSE for no logging.
<pre><code>define( 'DEBUG_LOG', '/path/to/writable/log/file' );
</code></pre>
or
<pre><code>define( 'DEBUG_LOG', TRUE );
</code></pre>
<h4>Todo</h4>
<ul>
<li>Add variable for sample rate so that this could run randomly on production installs</li>
<li>Admin panel per site</li>
<li>Admin panel globally</li>
<li>WordPress error logging</li>
<li>Mysql query logging</li>
<li>WP_Error integration</li>
<li>Alerts ex: if this takes more than this much memory then log it…</li>
</ul>

Debugger

You can use this plugin to manually log data or to capture logging on WordPress actions. You can capture load time, memory, backrace, data dumps, urls …

Debug Bar Slow Actions vs Debugger