Add caching for VideoPress functions with meta queries

[kienstra]

Changes proposed in this Pull Request:

• Caches functions that use WP_Query
• Adds some arguments to WP_Query to improve performance, like 'no_found_rows' => true
• Adds a few unit tests

Is this a new feature or does it add/remove features to an existing part of Jetpack?

• Enhances an existing feature, no intended change to functionality

Testing instructions:

(Regression testing for VideoPress)

1. Ensure VideoPress is enabled:
   

2. Create a new post

3. Add a Video block

4. Upload a video to it

5. Expected: the video plays in the editor.

6. Expected: the video plays on the front-end

Proposed changelog entry for your changes:

• Performance enhancement for VideoPress, caching and improving queries

[kienstra]

With unset( $video ); above, it looks like isset( $video->expires ) will never be true

[kraftbj]

Nice catch.

[jetpackbot]

Thank you for the great PR description!

When this PR is ready for review, please apply the [Status] Needs Review label. If you are an a11n, please have someone from your team review the code if possible. The Jetpack team will also review this PR and merge it to be included in the next Jetpack release.

Scheduled Jetpack release: April 7, 2020.
Scheduled code freeze: March 31, 2020

Generated by 🚫 dangerJS against c13c629

[kienstra]

There can be an error here if the query didn't find any posts.

[kienstra]

Maybe the cache expiration time should be different

[jeherve]

Quick question; did you consider using transients instead of object caching? Would it be better for performance on sites that do not use caching plugins?

[kienstra]

Good question, I'll look at that.

[kienstra]

Sure, I could add a transient here if you'd like.

But since the attachment ID is from a database query (WP_Query), I'm not sure that using a transient to store it in the database (wp_options) would be the best approach.

It would probably improve performance for sites without persistent object caching. But it could fill the wp_options table.

[dero]

@kienstra Expiring transients aren't autoloaded and are deleted once they expire.

Do you think we need to worry about polluting wp_options under these circumstances?

[dero]

@kienstra Also, is videopress_get_attachment_id_by_url ever called?

I think the original usage was in videopress_shortcode_override_for_core_shortcode (771097d), but has been superseded by 32dbcd7, but the method itself has never been removed.

I ran git log -p -S videopress_get_attachment_id_by_url to confirm.

[kienstra]

1. Use transients, but store only the post ID
2. We could use the object cache to store the post object, avoiding multiple calls to get_post() if we want.

Thanks, what do you think about the latest commits, which apply those 2 points?

[kienstra]

And to wrap things up, I'd get the post ID in a separate method, which would be a direct replacement for the method we are deprecating :) .

Hm, did you have in mind something like:

/**
 * Using a GUID, find a post ID.
 *
 * @param string $guid The guid to use to find the post ID.
 * @return int|false The post ID.
 */
function video_get_post_id_by_guid( $guid ) {
	$post = video_get_post_by_guid( $guid );

	if ( is_object( $post ) && 'WP_Post' === get_class( $post ) ) {
		return $post->ID;
	}

	return false;
}

[leogermani]

Thanks, what do you think about the latest commits, which apply those 2 points?

What I thought is that we can use both transients and wp_cache at the same time, each one for a purpose. Transients to store the post ID, so we avoid making the costly SQL SELECT many times though several requests. Object Caching to avoid calling get_post() several times within the same request.

Hm, did you have in mind something like:

Not exactly. I would actually leave the WP_Query call in video_get_post_id_by_guid, adding the 'fields' => 'ids'. I would call it from video_get_post_by_guid and then call get_post. So I would have the same behavior every time. (Always fetch the ID and then call get_post)

Looks a bit cleaner to me. Each method doing just one thing, and avoiding things like $cached_post sometimes holding the actual post, and sometimes holding just the post id.

Also it's important to add an expiration time for the transient.

This is how I see it. (Please consider this just as an opinion!)

function video_get_post_by_guid( $guid ) {
	// ...
	$cached_post = wp_cache_get( $cache_key, $cache_group );

	if ( $cached_post ) {
		return $cached_post;
	}

	$post_id = $this->video_get_post_id_by_guid( $guid );

	if ( is_int( $post_id ) ) {
		$post = get_post( $cached_post );
		wp_cache_set( $cache_key, $post, $cache_group, HOUR_IN_SECONDS );
		if ( $post ) {
			return $post;
		}
	}

}

function video_get_post_id_by_guid( $guid ) {
	// ... 
	$cached_id = get_transient( $cache_key );
	if ( $cached_id ) {
		return $cached_id;
	}

	// do the query
	set_transient( $cache_key, $id, HOUR_IN_SECONDS );
	return $id;
}

[kienstra]

Thanks, and sorry for the delay. I'm working on this.

[kienstra]

How does this look? It mainly uses your snippet above.

[kienstra]

Hi @dero,
Hope you're doing great.

Could you please review this?

[dero]

@kienstra Changes look good. I had a question about transients vs. wp_cache_* usage and I also think one of the methods that receives caching is no longer used in the codebase and can be removed.

[dero]

@kienstra Expiring transients aren't autoloaded and are deleted once they expire.

Do you think we need to worry about polluting wp_options under these circumstances?

[dero]

@kienstra Also, is videopress_get_attachment_id_by_url ever called?

I think the original usage was in videopress_shortcode_override_for_core_shortcode (771097d), but has been superseded by 32dbcd7, but the method itself has never been removed.

I ran git log -p -S videopress_get_attachment_id_by_url to confirm.

[kraftbj]

Marking for author reply pending resolution of the wp_cache_* vs transient question.

[kienstra]

Thanks, I responded above.

[leogermani]

Hi @kienstra ,

Thanks a lot for the changes.

There are few small things though:

• Use the fields => ids param in the query. Since this PR is all about performance, this is a must-have.
• Add the @since keywork to the new functions. (see https://make.wordpress.org/core/handbook/best-practices/inline-documentation-standards/php/#1-functions-class-methods)
• Now we have a perfect replacement for that deprecated function! Add there in the @see keyword there with our new function.
• I see that this file have functions prefixed both with video and with videopress. Most of them with videopress and, since this is the name of the module, we should stick to it. Those functions that are using only video as prefix we can review another time. But I think we should enforce the most appropriate prefix. So, change the prefix of the new functions to videopress

[kienstra]

I see that this file have functions prefixed both with video and with videopress. Most of them with videopress and, since this is the name of the module, we should stick to it. Those functions that are using only video as prefix we can review another time. But I think we should enforce the most appropriate prefix. So, change the prefix of the new functions to videopress

OK, is 64918b1 what you had in mind? It renames video_get_post_id_by_guid to videopress_get_post_id_by_guid()

[kienstra]

Hi @leogermani,
Thanks for your review. All 4 of your points are applied.

[leogermani]

Hi @kienstra ,

Thanks for all the work, it looks great now!

I had a quick chat with the team and we thought it was worth to rename one of the old functions to have a bit more consistency. I already did it since it doesn't change anything with the logic you implemented.

[kienstra]

Hi @leogermani,

I had a quick chat with the team and we thought it was worth to rename one of the old functions to have a bit more consistency. I already did it since it doesn't change anything with the logic you implemented.

Sounds good, thanks for pushing that change.