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WordPress

_maybe_update_themes()

Since
2.7.0
Source
wp-includes/update.php:1043
Checks themes versions only after a duration of time.

Description

This is for performance reasons to make sure that on the theme version checker is not run on every page load.

Compatibility

WordPress
since 2.7.0
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.

Performance profile

How much work a call to _maybe_update_themes() 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
Expensive

Reaches an outbound HTTP request via wp_remote_post().

Scaling
Constant

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

Instructions
9–17

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 18.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

  • transienttransientget_site_transient()called directly
  • hookthird-party callbacksapply_filters()one call below _maybe_update_themes()
  • cacheobject cachewp_cache_get()one call below _maybe_update_themes()
  • optionnetwork optionget_site_option()one call below _maybe_update_themes()
  • httpoutbound HTTP requestwp_remote_post()one call below _maybe_update_themes()

Further down the call graph this can also reach serialize and query. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 3 distinct outcomes

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

WhenInstructionsCalls it makes
!isset($current)9get_site_transient(), wp_update_themes()
isset($current)15get_site_transient(), time()
isset($current)17get_site_transient(), time(), wp_update_themes()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 18 instructions, 9–17 executed per call, 2 branches. The work does not change between versions.

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

Source code

View on Trac View on GitHub 

function _maybe_update_themes() {	$current = get_site_transient( 'update_themes' ); 	if ( isset( $current->last_checked )		&& 12 * HOUR_IN_SECONDS > ( time() - $current->last_checked )	) {		return;	} 	wp_update_themes();}

Changelog

Introduced in 2.7.0. 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 6.8.8 tag, from src/wp-includes/update.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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