wpdb::determine_charset( string $charset, string $collate ): array
- Since
- 4.6.0
- Source
wp-includes/class-wpdb.php:881
Description
For example, when able, utf8mb4 should be used instead of utf8.
Compatibility
- WordPress
- since 4.6.0
- 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
$charsetstring- The character set to check.
$collatestring- The collation to check.
Return value
array- The most appropriate character set and collation to use.
$charsetstringCharacter set.$collatestringCollation.
Performance profile
How much work a call to wpdb::determine_charset() 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
- Trivial
- Scaling
- Constant
- Instructions
- 10–30
- Plugin surface
- None
- Called by
- 1
Touches nothing outside its own arguments.
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 37.
Nothing here hands control to plugin code.
1 place in core call this, so the cost is paid more often than your own code shows.
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 wpdb::determine_charset() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 10–12 | compact() |
$value instanceof && !empty($value) | 20–30 | ->has_cap(), compact() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 37 | 10–30 | 8 | |
| 8.5 | 37 | 10–30 | 8 | |
| 8.4 | 37 | 10–30 | 8 | 3 fewer instructions than PHP 8.3 |
| 8.3 | 40 | 10–33 | 8 | |
| 8.2 | 40 | 10–33 | 8 | |
| 8.1 | 40 | 10–33 | 8 | |
| 7.4 | 40 | 10–33 | 8 |
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 · 1
- wpdb::has_cap()Determines whether the database or WPDB supports a particular feature.
Used by · 1
- wpdb::init_charset()Sets $this->charset and $this->collate.
Source code
public function determine_charset( $charset, $collate ) { if ( ( ! ( $this->dbh instanceof mysqli ) ) || empty( $this->dbh ) ) { return compact( 'charset', 'collate' ); } if ( 'utf8' === $charset ) { $charset = 'utf8mb4'; } if ( 'utf8mb4' === $charset ) { // _general_ is outdated, so we can upgrade it to _unicode_, instead. if ( ! $collate || 'utf8_general_ci' === $collate ) { $collate = 'utf8mb4_unicode_ci'; } else { $collate = str_replace( 'utf8_', 'utf8mb4_', $collate ); } } // _unicode_520_ is a better collation, we should use that when it's available. if ( $this->has_cap( 'utf8mb4_520' ) && 'utf8mb4_unicode_ci' === $collate ) { $collate = 'utf8mb4_unicode_520_ci'; } return compact( 'charset', 'collate' ); }Changelog
Introduced in 4.6.0. 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 7.0.4 tag, from
src/wp-includes/class-wpdb.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.