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WP_Metadata_Lazyloader::lazyload_meta_callback( mixed $check, int $object_id, string $meta_key, bool $single, string $meta_type ): mixed

Since
6.3.0
Source
wp-includes/class-wp-metadata-lazyloader.php:183
Lazy-loads meta for queued objects.

Description

This method is public so that it can be used as a filter callback. As a rule, there is no need to invoke it directly.

Compatibility

WordPress
since 6.3.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$checkmixed
The $check param passed from the 'get_*_metadata' hook.
$object_idint
ID of the object metadata is for.
$meta_keystring
Unused.
$singlebool
Unused.
$meta_typestring
Type of object metadata is for. Accepts 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.

Return value

mixed
In order not to short-circuit get_metadata(). Generally, this is null, but it could be another value if filtered by a plugin.

Performance profile

How much work a call to WP_Metadata_Lazyloader::lazyload_meta_callback() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Light

Only touches the object cache, via wp_cache_get_multiple().

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
9–28

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 29.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
2

2 places in core call this, so the cost is paid more often than your own code shows.

What it touches

  • hookthird-party callbacksapply_filters()one call below WP_Metadata_Lazyloader::lazyload_meta_callback()
  • cacheobject cachewp_cache_get_multiple()one call below WP_Metadata_Lazyloader::lazyload_meta_callback()

What one call costs · 2 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Metadata_Lazyloader::lazyload_meta_callback() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
empty($meta_type)9none
!empty($meta_type)23–28array_keys(), update_meta_cache(), ->reset_queue()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev299–283
8.5299–283
8.4299–2833 fewer instructions than PHP 8.3
8.3329–313
8.2329–313
8.1329–313
7.4329–313

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 2

Used by · 2

Source code

	public function lazyload_meta_callback( $check, $object_id, $meta_key, $single, $meta_type ) {		if ( empty( $this->pending_objects[ $meta_type ] ) ) {			return $check;		} 		$object_ids = array_keys( $this->pending_objects[ $meta_type ] );		if ( $object_id && ! in_array( $object_id, $object_ids, true ) ) {			$object_ids[] = $object_id;		} 		update_meta_cache( $meta_type, $object_ids ); 		// No need to run again for this set of objects.		$this->reset_queue( $meta_type ); 		return $check;	}

Changelog

Introduced in 6.3.0. Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-wp-metadata-lazyloader.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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