[wp-trac] [WordPress Trac] #50679: Optimization for wp_get_attachment_metadata()

[WordPress Trac]

#50679: Optimization for wp_get_attachment_metadata()
-------------------------+------------------------------
 Reporter:  Tkama        |       Owner:  (none)
     Type:  enhancement  |      Status:  new
 Priority:  normal       |   Milestone:  Awaiting Review
Component:  Media        |     Version:  5.4.2
 Severity:  normal       |  Resolution:
 Keywords:               |     Focuses:  performance
-------------------------+------------------------------

Comment (by Tkama):

 {{{#!php
 <?php
 // attachment invalid ID
 $attachment_id = 'aa1342';
 $post = get_post( $attachment_id = (int) $attachment_id );
 // 0.0000001 sec.
 $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
 // 0.0000001 sec.

 for( $i=1; $i<50000; $i++ ){
     $post = get_post( $attachment_id = (int) $attachment_id );
 // 0.010389 sec.
     $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true
 ); // 0.005079 sec.
 }

 // this attachment exists
 $attachment_id = 13423;
 clean_post_cache( $attachment_id );
 $post = get_post( $attachment_id = (int) $attachment_id );
 // 0.000927 sec.
 $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
 // 0.001256 sec.

 for( $i=1; $i<50000; $i++ ){
     $post = get_post( $attachment_id = (int) $attachment_id );
 // 0.126539 sec.
     $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true
 ); // 0.210088 sec.
 }


 // attachment NOT exists
 $attachment_id = 13423333;
 clean_post_cache( $attachment_id );
 $post = get_post( $attachment_id = (int) $attachment_id );
 // 0.000516 sec.
 $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true );
 // 0.000432 sec.

 for( $i=1; $i<50000; $i++ ){
     $post = get_post( $attachment_id = (int) $attachment_id );
 // 10.004103 sec.
     $data = get_post_meta( $attachment_id, '_wp_attachment_metadata', true
 ); // 0.199436 sec.
 }

 }}}

 NOTE about code: each line of code with benchmark was run separately.

 My conclusion: we no need any additional checks to run `get_post_meta()` —
 code above it only slow down the code. We even can't pass WP_Post object
 into the `wp_get_attachment_metadata()` to increase the function speed.
 For example, I need to call `wp_get_attachment_metadata()` more then 1200
 times per site page generation and I have no choice except use
 `get_post_meta( $post->ID, '_wp_attachment_metadata', true )` directly.

 P.S. I was shocked when seen `get_post()` for not existence attachment -
 10.004103 sec. fro 50k iterations.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/50679#comment:3>
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