wp-admin/includes/upgrade.php:2685Drops a specified index from a table.
$tablestring$indexstringtruefunction 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;}Introduced in 1.0.1. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-admin/includes/upgrade.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.