WP_Tax_Query::find_compatible_table_alias( array $clause, array $parent_query ): string|false
- Since
- 4.1.0
- Source
wp-includes/class-wp-tax-query.php:505
Description
We avoid unnecessary table joins by allowing each clause to look for an existing table alias that is compatible with the query that it needs to perform.
An existing alias is compatible if (a) it is a sibling of $clause (ie, it's under the scope of the same relation), and (b) the combination of operator and relation between the clauses allows for a shared table join. In the case of WP_Tax_Query, this only applies to 'IN' clauses that are connected by the relation 'OR'.
Compatibility
- WordPress
- since 4.1.0
- 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
$clausearray- Query clause.
$parent_queryarray- Parent query of $clause.
Return value
string|false- Table alias if found, otherwise false.
Performance profile
How much work a call to WP_Tax_Query::find_compatible_table_alias() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Light
- Scaling
- Scales with input
- Instructions
- 6–36
- Plugin surface
- None
- Called by
- 1
Touches nothing outside its own arguments.
The body loops, so the work grows with what you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 38.
Nothing here hands control to plugin code.
1 place in core call this, so the cost is paid more often than your own code shows.
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Tax_Query::find_compatible_table_alias() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 6–17 | none |
isset($clause) && isset($parent_query) && !$parent_query && is_array($sibling) && ->is_first_order_clause() && !empty($sibling) | 36 | ->is_first_order_clause(), strtoupper() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 38 | 6–36 | 11 | |
| 8.5 | 38 | 6–36 | 11 | |
| 8.4 | 38 | 6–36 | 11 | 4 fewer instructions than PHP 8.3 |
| 8.3 | 42 | 6–40 | 11 | |
| 8.2 | 42 | 6–40 | 11 | |
| 8.1 | 42 | 6–40 | 11 | |
| 7.4 | 42 | 6–40 | 11 |
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
- WP_Tax_Query::is_first_order_clause()Determines whether a clause is first-order.
Used by · 1
- WP_Tax_Query::get_sql_for_clause()Generates SQL JOIN and WHERE clauses for a "first-order" query clause.
Source code
protected function find_compatible_table_alias( $clause, $parent_query ) { $alias = false; // Confidence check. Only IN queries use the JOIN syntax. if ( ! isset( $clause['operator'] ) || 'IN' !== $clause['operator'] ) { return $alias; } // Since we're only checking IN queries, we're only concerned with OR relations. if ( ! isset( $parent_query['relation'] ) || 'OR' !== $parent_query['relation'] ) { return $alias; } $compatible_operators = array( 'IN' ); foreach ( $parent_query as $sibling ) { if ( ! is_array( $sibling ) || ! $this->is_first_order_clause( $sibling ) ) { continue; } if ( empty( $sibling['alias'] ) || empty( $sibling['operator'] ) ) { continue; } // The sibling must both have compatible operator to share its alias. if ( in_array( strtoupper( $sibling['operator'] ), $compatible_operators, true ) ) { $alias = preg_replace( '/\W/', '_', $sibling['alias'] ); break; } } return $alias; }Changelog
Introduced in 4.1.0. 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 6.8.8 tag, from
src/wp-includes/class-wp-tax-query.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.