Make WordPress Core

Opened 4 weeks ago

Last modified 11 days ago

#61234 new defect (bug)

Investigation Request: High Frequency of `hooked_block_types` Filter Calls

Reported by: mreishus's profile mreishus Owned by:
Milestone: Awaiting Review Priority: normal
Severity: normal Version: 6.5
Component: Editor Keywords:
Focuses: performance Cc:


I have identified a potential performance concern related to the hooked_block_types filter in WordPress 6.5.3, particularly regarding its scalability when a site has a large number of blocks and custom patterns.

Steps to Reproduce:

  1. Environment Setup:
    • Installed a completely blank 6.5.3 site using the default Twenty Twenty-Four theme.

  1. Customization:
    • Installed and activated a custom plugin to count the number of times the hooked_block_types filter is applied. The plugin code is as follows:
Plugin Name: Hooked Block Types Counter
Description: A simple plugin to count how many times the 'hooked_block_types' filter is applied.
Version: 1.0
Author: Your Name

function init_hooked_block_types_counter() {
    $GLOBALS['hooked_block_types_count'] = 0;
add_action('init', 'init_hooked_block_types_counter');

function increment_hooked_block_types_count($hooked_block_types, $relative_position, $anchor_block_type, $context) {
    return $hooked_block_types; // Returning the original list without modification
add_filter('hooked_block_types', 'increment_hooked_block_types_count', 10, 4);

function log_hooked_block_types_count() {
    $count = $GLOBALS['hooked_block_types_count'];
    error_log("The 'hooked_block_types' filter was run $count times.");
add_action('shutdown', 'log_hooked_block_types_count');
  1. Initial Observation:
    • Visiting the front page with the default Twenty Twenty-Four theme and no additional content shows:
      [16-May-2024 22:03:09 UTC] The 'hooked_block_types' filter was run 526 times.
  1. Adding Content:
    • Using the Site Editor, edited the Index template by adding a Columns block, with a few Paragraph blocks in each column.
    • After saving the changes and visiting the home page again, it showed:
      [16-May-2024 22:09:02 UTC] The 'hooked_block_types' filter was run 590 times.


  • While the out-of-the-box performance might be acceptable, the issue scales significantly with added content.
  • On a site with extensive custom patterns, I observed the filter being applied approximately 9,800 times.
  • This scalability concern implies that functions hooked to hooked_block_types could potentially run thousands of times, which can have significant performance implications.
  • For example, Jetpack’s sharing-button.php hooks into this filter and runs the following check: ( new Modules() )->is_active( 'sharedaddy' ). Running such a check 10,000 times seems inefficient and could lead to performance bottlenecks. Authors writing code on this hook might be unaware it could be run thousands of times.


Jetpack’s sharing-button.php:


  • Investigate why the hooked_block_types filter is being applied so many times.
  • Consider optimizing the filter application to reduce redundancy and improve performance.
  • Provide guidelines or best practices for plugin authors to avoid performance issues when hooking into hooked_block_types.

Thank you for looking into this matter. I believe addressing this will help improve the performance and scalability of WordPress sites, especially those with complex block structures and custom patterns.

Change History (5)

#1 @swissspidy
4 weeks ago

  • Component changed from General to Editor
  • Focuses performance added

This ticket was mentioned in Slack in #core-performance by mukeshpanchal27. View the logs.

4 weeks ago

#3 @mukesh27
4 weeks ago

  • Version changed from 6.5.3 to 6.5

#4 @Bernhard Reiter
4 weeks ago

Tangentially, we started an experiment a while ago that would replace the parsing/traversal/re-serialization with a streaming parser, which we hope will improve performance. We haven’t been working on this for a while but might get back to it some time after 6.6.

This ticket was mentioned in Slack in #core-performance by mukeshpanchal27. View the logs.

11 days ago

Note: See TracTickets for help on using tickets.