Query Monitor
Query Monitor is the developer tools panel for WordPress and WooCommerce. It enables debugging of database queries, PHP errors, hooks and actions, block editor blocks, enqueued scripts and stylesheets, HTTP API calls, and more.
It includes some advanced features such as debugging of Ajax calls, REST API calls, user capability checks, and full support for block themes and full site editing. It includes the ability to narrow down much of its output by plugin or theme, allowing you to quickly determine poorly performing plugins, themes, or functions.
Query Monitor focuses heavily on presenting its information in a useful manner. Here's an example showing aggregate database queries grouped by the components responsible for them:
Features
Database Queries
- Shows all database queries performed during the current request
- Shows affected rows and time taken for all queries
- Shows notifications for slow queries, duplicate queries, and queries with errors
- Shows aggregate query information grouped by type, component, or calling function
- Queries can be filtered by query type, component, or calling function
Filtering queries by component or calling function makes it easy to see which plugins, themes, or functions on your site are making the most (or the slowest) database queries.
Hooks & Actions
- Shows all hooks fired during the current request, along with action callbacks, priorities, and components
- Actions can be filtered by component or name
Theme
- Shows the template filename and complete template hierarchy
- Shows all template parts that were requested, and whether they were loaded or not
- Shows the available body classes
- Fully supports block themes and full site editing (FSE)
PHP Errors
- Shows PHP warnings, notices, stricts, and deprecated errors, formatted nicely along with their component and call stack
- Shows a visible warning in the admin toolbar when necessary
Doing it Wrong
- Shows usage of "Doing it Wrong" or "Deprecated" functionality in the code on your site
Block Content
- Shows blocks and associated information from post content and full site editing
Request
- Shows information about matched URL rewrite rules for the request and corresponding query parameters
- Shows query variables and highlights any that are custom
Scripts & Styles
- Shows all enqueued scripts and styles along with their handle, URL, and version
- Shows their dependencies and dependents
- Alerts you to any broken or missing dependencies
- Supports the script modules feature added in WordPress 6.5
Languages
- Shows you language settings and loaded text domains
- Shows you the requested MO, JSON, and PHP translation files for each text domain and which ones were loaded
HTTP API Requests
- Shows all server-side HTTP requests (as long as they use the WordPress HTTP API)
- Shows the response code, call stack, component, timeout, response size, time taken, and other meta data
- Alerts you to erroneous responses, such as failed requests and anything without a
200 response code
- Supports Guzzle HTTP requests via an optional middleware for comprehensive HTTP debugging
User Capability Checks
- Shows every user capability check that is performed, along with the result and any parameters passed along with the capability check
Multisite
- Shows all calls to
switch_to_blog() and restore_current_blog() on Multisite installations
Redirects
- Whenever a server-side redirect occurs, Query Monitor adds an
X-QM-Redirect HTTP header containing the call stack, so you can use your favourite HTTP inspector or browser developer tools to trace where a redirect has come from
Ajax
The response from any jQuery Ajax request on the page will contain various debugging information in its headers. Any errors also get output to the developer console. No hooking required.
Currently this includes PHP errors and some overview information such as memory usage, but this will be built upon in future versions.
REST API
The response from an authenticated WordPress REST API request will contain various debugging information in its headers, as long as the authenticated user has permission to view Query Monitor's output.
Read more about debugging REST API requests with Query Monitor.
Admin Screen
- Shows the correct names for custom column filters and actions on all admin screens that use a list table
- Shows the state of
get_current_screen() and a few global variables
Environment Information
- Shows PHP information such as memory limit, error reporting levels, and values of various constants
- Shows MySQL or MariaDB information, including caching and performance related configuration
- Shows information about WordPress and the web server
- Shows version numbers for all the things
Logging
Debugging messages can be sent to the Logs panel using actions. This works as a good replacement for var_dump():
do_action( 'qm/debug', 'This happened!' );
The logger is PSR-3 compatible, so you can use any of the following actions which correspond to PSR-3 log levels:
qm/debugqm/infoqm/noticeqm/warningqm/errorqm/criticalqm/alertqm/emergency
This is the beginning of the README. Read the rest at the original. Read the full README ↗
