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function is not described

_prime_site_caches() WP 4.6.0

Adds any sites from the given IDs to the cache that do not already exist in cache.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

No Hooks.


null. Nothing.


_prime_site_caches( $ids, $update_meta_cache );
$ids(array) (required)
ID list.
Whether to update the meta cache.
Default: true


  • See: update_site_cache()
  • Global. wpdb. $wpdb WordPress database abstraction object.


Since 4.6.0 Introduced.
Since 5.1.0 Introduced the $update_meta_cache parameter.

Code of _prime_site_caches() WP 5.7.2

function _prime_site_caches( $ids, $update_meta_cache = true ) {
	global $wpdb;

	$non_cached_ids = _get_non_cached_ids( $ids, 'sites' );
	if ( ! empty( $non_cached_ids ) ) {
		$fresh_sites = $wpdb->get_results( sprintf( "SELECT * FROM $wpdb->blogs WHERE blog_id IN (%s)", implode( ',', array_map( 'intval', $non_cached_ids ) ) ) ); // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared

		update_site_cache( $fresh_sites, $update_meta_cache );