metadata_exists( string $meta_type, int $object_id, string $meta_key ): bool
- Since
- 3.3.0
- Source
wp-includes/meta.php:763
Compatibility
- WordPress
- since 3.3.0
- 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
$meta_typestring- Type of object metadata is for. Accepts 'blog', 'post', 'comment', 'term', 'user', or any other object type with an associated meta table.
$object_idint- ID of the object metadata is for.
$meta_keystring- Metadata key.
Return value
bool- Whether a meta field with the given key exists.
Performance profile
How much work a call to metadata_exists() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Light
- Scaling
- Constant
- Instructions
- 5–43
- Plugin surface
- 1 hook
- Called by
- 4
Only touches the object cache, via wp_cache_get().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 48.
Third-party callbacks on 'get_{$meta_type}_metadata' run inside this call, and their cost is not bounded by anything here.
4 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
apply_filters()called directly - cacheobject cache
wp_cache_get()called directly
What one call costs · 4 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost metadata_exists() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 5–7 | none |
$object_id | 12 | absint() |
$object_id && $check !== null | 27 | absint(), apply_filters() |
$object_id && $check === null | 35–43 | absint(), apply_filters(), wp_cache_get() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 48 | 5–43 | 6 | |
| 8.5 | 48 | 5–43 | 6 | |
| 8.4 | 48 | 5–43 | 6 | 2 fewer instructions than PHP 8.3 |
| 8.3 | 50 | 5–45 | 6 | |
| 8.2 | 50 | 5–45 | 6 | |
| 8.1 | 50 | 5–45 | 6 | |
| 7.4 | 50 | 5–45 | 6 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Hooks and filters fired · 1
One hook fires while metadata_exists() runs, in this order:
- apply_filters( get_{$meta_type}_metadata )filterline 774 (+11 into the body)
Short-circuits the return value of a meta field.
Uses · 4
- absint()Converts a value to non-negative integer.
- apply_filters()Calls the callback functions that have been added to a filter hook.
- wp_cache_get()Retrieves the cache contents from the cache by key and group.
- update_meta_cache()Updates the metadata cache for the specified objects.
Used by · 4
- WP_Post::__isset()Isset-er.
- WP_User::__isset()Magic method for checking the existence of a certain custom field.
- wp_install_defaults()Creates the initial content for a newly-installed site.
- wp_save_revisioned_meta_fields()Save the revisioned meta fields.
Source code
function metadata_exists( $meta_type, $object_id, $meta_key ) { if ( ! $meta_type || ! is_numeric( $object_id ) ) { return false; } $object_id = absint( $object_id ); if ( ! $object_id ) { return false; } /** This filter is documented in wp-includes/meta.php */ $check = apply_filters( "get_{$meta_type}_metadata", null, $object_id, $meta_key, true, $meta_type ); if ( null !== $check ) { return (bool) $check; } $meta_cache = wp_cache_get( $object_id, $meta_type . '_meta' ); if ( ! $meta_cache ) { $meta_cache = update_meta_cache( $meta_type, array( $object_id ) ); $meta_cache = $meta_cache[ $object_id ]; } if ( isset( $meta_cache[ $meta_key ] ) ) { return true; } return false;}Changelog
Introduced in 3.3.0. Unchanged from 6.7.7 through 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/meta.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.