Backend performance slow on certain block(s)....

[GlennMartin1]

Describe the bug
Generally I have fast performance, except on pages like these:
https://www.disciples-fellowship.org/messages-2018/
https://www.disciples-fellowship.org/messages-2017/

These pages have about 40 Columns blocks, and about 40 Audio blocks.

Column 1 has a Paragraph block; Column 2 has an Audio block. This is repeated through about 40 occurrences.

I assume it's either the Columns or Audio. I have not researched which one makes the slow performance.

To Reproduce

1. Create a page with many Columns blocks
2. Create a page with many Audio blocks.
3. backend performance is really bad....

Been experiencing this since these pages were created (about 3.0 (+/-) to the current 4.3).

[dmsnell]

hi @GlennMartin1. I jumped in here because I thought that maybe some issues were related to work I've recently done but I can't reproduce your problem.

in an effort to try I created the structure you're talking about: repeated column blocks containing two columns, a left side with a paragraph block and a right side with an audio block. I duplicated these and have been working with one that has 864 copies of it, so hopefully a worst-case kind of situation.

<!-- wp:columns -->
<div class="wp-block-columns has-2-columns"><!-- wp:column -->
<div class="wp-block-column"><!-- wp:paragraph -->
<p>Explanation</p>
<!-- /wp:paragraph --></div>
<!-- /wp:column -->

<!-- wp:column -->
<div class="wp-block-column"><!-- wp:audio {"id":2608} -->
<figure class="wp-block-audio"><audio controls src="some-url"></audio></figure>
<!-- /wp:audio --></div>
<!-- /wp:column --></div>
<!-- /wp:columns -->

to render my post with these copies WordPress only takes 46ms on my computer - a late 2013 MBP with a 2.6 GHz quad-core i7.

it takes a while after pasting the code into the code editor, waited minutes inside the code editor to switch into visual mode before it crashed, but page render seems fine.

loading up a server in Docker it only took 199ms for the first-time-to-byte metric in Chrome. that is, it took 199ms to initialize WordPress, load the post content, parse the document, and render the output from the blocks.

---

I was hoping that maybe you could help us out in a couple of ways…

1. define what you are measuring when you say "backend performance." what do you consider the backend and how do you know it's slow?
2. have you tried a copy of this post in a fresh WordPress install? could there be a plugin doing some extra processing over the content that might be slowing things down?
3. can you share actual timing results you have gotten? can you share the post_content for one of the slow pages?

[lkraav]

@dmsnell I have "performance-problem" content and staging site access I can share to demonstrate reproduction. What's a private medium we can exchange access credentials on? EDIT answer: WP Core Slack, of course, duh.

PS yep, Column blocks are involved.

[GlennMartin1]

Thanks for your patience.

In my case, yes, the page renders fine. The issue is slow response when typing, focus changes, etc...

For example, if I create type into a paragraph block, it may not show on the screen until I wait a second or two.

Same thing when I click on another block; it doesn't get focus for a second or two, and it feels like it didn't get the mouse click - until suddenly I see it catch up.

That general slowness is in many operations - but again, only on these two pages. Otherwise, I have no performance problems elsewhere on any Gutenberg site.

I have not done any timing. It's not super L-O-N-G, but it's it's easily long enough to notice and get confused why nothing is immediately appearing as I try to interact with a page.

My theme is Storefront (by WooCommerce).

The active plugins are 11 popular ones:

• Akismet Anti-Spam
• Contact Form 7
• Google Analytics Dashboard
• Gutenberg
• ManageWP - Worker
• Print Post and Page
• Storefront Blog Customiser
• Storefront Footer Bar
• Storefront Powerpack
• WooCommerce Helper
• Yoast SEO

I could create a staging site and give credentials, if that would be helpful.

I have not copied the post to another install. All my installs are on the same setup (WP-Engine), and my site otherwise is very fast.