WordPress at a glance
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.

Return

null. Nothing.

Usage

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

Notes

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

Changelog

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

Code of _prime_site_caches() WP 5.7.2

<?php
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 );
	}
}