Improve performance of function "wp_update_attachment_metadata" in post.php

[lucasbustamante]

I had to import thousands of images to WordPress and it was taking an average of 5 seconds to upload each image, even though they were all on localhost, so WordPress only had to move it and register it in the database.

To speed up this process, I debugged each and every call made during a media upload, and found out the great guilty that, after a little tweak, made my media upload going from 5 seconds to 0.7 seconds.

What was slowing it down was add_filter('wp_update_attachment_metadata', $data, $post->ID) inside function wp_update_attachment_metadata() in post.php:

<?php
/**
 * Update metadata for an attachment.
 *
 * @since 2.1.0
 *
 * @param int   $attachment_id Attachment post ID.
 * @param array $data          Attachment meta data.
 * @return int|bool False if $post is invalid.
 */
function wp_update_attachment_metadata( $attachment_id, $data ) {
        $attachment_id = (int) $attachment_id;
        if ( ! $post = get_post( $attachment_id ) ) {
                return false;
        }

        /**
         * Filters the updated attachment meta data.
         *
         * @since 2.1.0
         *
         * @param array $data          Array of updated attachment meta data.
         * @param int   $attachment_id Attachment post ID.
         */
        if ( $data = apply_filters( 'wp_update_attachment_metadata', $data, $post->ID ) )
                return update_post_meta( $post->ID, '_wp_attachment_metadata', $data );
        else
                return delete_post_meta( $post->ID, '_wp_attachment_metadata' );
}

As I had to upload thousands of images, I modified it to this, just during the import:

<?php
/**
 * Update metadata for an attachment.
 *
 * @since 2.1.0
 *
 * @param int   $attachment_id Attachment post ID.
 * @param array $data          Attachment meta data.
 * @return int|bool False if $post is invalid.
 */
function wp_update_attachment_metadata( $attachment_id, $data ) {
        $attachment_id = (int) $attachment_id;
        if ( ! $post = get_post( $attachment_id ) ) {
                return false;
        }

        /**
         * Filters the updated attachment meta data.
         *
         * @since 2.1.0
         *
         * @param array $data          Array of updated attachment meta data.
         * @param int   $attachment_id Attachment post ID.
         */
        if (WP_DOING_IMPORT) {
                return update_post_meta( $post->ID, '_wp_attachment_metadata', $data );
        }
        if ( $data = apply_filters( 'wp_update_attachment_metadata', $data, $post->ID ) )
                return update_post_meta( $post->ID, '_wp_attachment_metadata', $data );
        else
                return delete_post_meta( $post->ID, '_wp_attachment_metadata' );
}

Before the tweak:

  'uploadtimedebug_start' => 0 seconds
  'uploadtimedebug_after_requires' => 0.006 seconds
  'uploadtimedebug_after_tmp_filled' => 0.597 seconds
  'uploadtimedebug_before_media_handle_sideload' => 0.597 seconds
  'uploadtimedebug_after_media_handle_sideload' => 5.370 seconds
  'uploadtimedebug_finish' => 5.370 seconds

After the tweak:

  'uploadtimedebug_inicio' => 0 seconds
  'uploadtimedebug_after_requires' => 0.007 seconds
  'uploadtimedebug_after_tmp_filled' => 0.620 seconds
  'uploadtimedebug_before_media_handle_sideload' => 0.620 seconds
  'uploadtimedebug_after_media_handle_sideload' => 0.723 seconds
  'uploadtimedebug_finish' => 0.723 seconds

I wonder if we could improve this piece of code to be more performant?

[lucasbustamante]

Please ignore this ticket, it was the plugin "Smush it" that was slowing down the uploads.