wppaste
WordPress

drop_index( string $table, string $index ): true

Since
1.0.1
Source
wp-admin/includes/upgrade.php:2715
Drops a specified index from a table.

Compatibility

WordPress
since 1.0.1
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

$tablestring
Database table name.
$indexstring
Index name to drop.

Return value

true
True, when finished.

Performance profile

How much work a call to drop_index() 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

Reaches the database via ->query().

Scaling
Scales with input

The body loops, so the work grows with what you pass in.

Instructions
20

Executed per call on PHP 8.5. The body compiles to 31.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
1

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

What it touches

  • sqldatabase query->query()called directly

What one call costs · 1 distinct outcome

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

WhenInstructionsCalls it makes
!$i20->hide_errors(), ->query(), ->show_errors()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 31 instructions, 20 executed per call, 1 branch. 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.

Used by · 1

Source code

View on Trac View on GitHub 

function drop_index( $table, $index ) {	global $wpdb; 	$wpdb->hide_errors(); 	$wpdb->query( "ALTER TABLE `$table` DROP INDEX `$index`" ); 	// Now we need to take out all the extra ones we may have created.	for ( $i = 0; $i < 25; $i++ ) {		$wpdb->query( "ALTER TABLE `$table` DROP INDEX `{$index}_$i`" );	} 	$wpdb->show_errors(); 	return true;}

Changelog

Introduced in 1.0.1. 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 7.0.4 tag, from src/wp-admin/includes/upgrade.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
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