function DrupalDatabaseCache::getMultiple

Implements DrupalCacheInterface::getMultiple().

Overrides DrupalCacheInterface::getMultiple

File

includes/cache.inc, line 347

Class

DrupalDatabaseCache

Defines a default cache implementation.

Code

function getMultiple(&$cids) {
    try {
        // Garbage collection necessary when enforcing a minimum cache lifetime.
        $this->garbageCollection($this->bin);
        // When serving cached pages, the overhead of using db_select() was found
        // to add around 30% overhead to the request. Since $this->bin is a
        // variable, this means the call to db_query() here uses a concatenated
        // string. This is highly discouraged under any other circumstances, and
        // is used here only due to the performance overhead we would incur
        // otherwise. When serving an uncached page, the overhead of using
        // db_select() is a much smaller proportion of the request.
        $result = db_query('SELECT cid, data, created, expire, serialized FROM {' . db_escape_table($this->bin) . '} WHERE cid IN (:cids)', array(
            ':cids' => $cids,
        ));
        $cache = array();
        foreach ($result as $item) {
            $item = $this->prepareItem($item);
            if ($item) {
                $cache[$item->cid] = $item;
            }
        }
        $cids = array_diff($cids, array_keys($cache));
        return $cache;
    } catch (Exception $e) {
        // If the database is never going to be available, cache requests should
        // return FALSE in order to allow exception handling to occur.
        return array();
    }
}