delete_expired_transients() │ WP 4.9.0

Deletes all expired transient options.

Removing transient options will clean up the options table in the database. Sometimes plugins store data in transient options but do not delete them, and it may happen that such data becomes very large.

Running this function does not harm the site in any way.

Does nothing if an object caching plugin is used on the site and the $force_db parameter is disabled (disabled by default).

Since WP 3.7, expired transient options are automatically deleted when updating WordPress (upgrading the WordPress database).

Since version 4.9, this function is by default hooked to cron and runs every day.

Read about transient options in the description of the function set_transient().

No Hooks.

Returns

null. Nothing (null)

Usage

delete_expired_transients( $force_db );
$force_db(boolean)
If set to true, transient options will be forcibly deleted from the database, even if an object caching plugin is used.
Default: false

Examples

0

#1 Delete all temporary options that have expired their lifetime 

delete_expired_transients( true );

Notes

  • Global. wpdb. $wpdb WordPress database abstraction object.

Changelog

Since 4.9.0 Introduced.

delete_expired_transients() code WP 6.9.1

wp-includes/option.php 
function delete_expired_transients( $force_db = false ) {
	global $wpdb;

	if ( ! $force_db && wp_using_ext_object_cache() ) {
		return;
	}

	$wpdb->query(
		$wpdb->prepare(
			"DELETE a, b FROM {$wpdb->options} a, {$wpdb->options} b
			WHERE a.option_name LIKE %s
			AND a.option_name NOT LIKE %s
			AND b.option_name = CONCAT( '_transient_timeout_', SUBSTRING( a.option_name, 12 ) )
			AND b.option_value < %d",
			$wpdb->esc_like( '_transient_' ) . '%',
			$wpdb->esc_like( '_transient_timeout_' ) . '%',
			time()
		)
	);

	if ( ! is_multisite() ) {
		// Single site stores site transients in the options table.
		$wpdb->query(
			$wpdb->prepare(
				"DELETE a, b FROM {$wpdb->options} a, {$wpdb->options} b
				WHERE a.option_name LIKE %s
				AND a.option_name NOT LIKE %s
				AND b.option_name = CONCAT( '_site_transient_timeout_', SUBSTRING( a.option_name, 17 ) )
				AND b.option_value < %d",
				$wpdb->esc_like( '_site_transient_' ) . '%',
				$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
				time()
			)
		);
	} elseif ( is_main_site() && is_main_network() ) {
		// Multisite stores site transients in the sitemeta table.
		$wpdb->query(
			$wpdb->prepare(
				"DELETE a, b FROM {$wpdb->sitemeta} a, {$wpdb->sitemeta} b
				WHERE a.meta_key LIKE %s
				AND a.meta_key NOT LIKE %s
				AND b.meta_key = CONCAT( '_site_transient_timeout_', SUBSTRING( a.meta_key, 17 ) )
				AND b.meta_value < %d",
				$wpdb->esc_like( '_site_transient_' ) . '%',
				$wpdb->esc_like( '_site_transient_timeout_' ) . '%',
				time()
			)
		);
	}
}

_transient (options)