好吧，这本身并不是一个完整的解决方案，但我将从隔离问题是SQL查询还是wp_mail() 呼叫如果您注释掉wp_mail() 第行，您可以了解函数运行查询和构建消息所需的时间，而无需尝试发送它们。

如果您突然发现该功能的速度非常快，那么可以肯定的是，邮件连接会让您的速度变慢，但不幸的是，这会打开另一罐蠕虫，因为电子邮件配置可能因web主机而异。

另一方面，如果函数同样慢，那么查询很可能是罪魁祸首，那么查看Wordpress生成的实际SQL将非常有帮助，以尝试识别性能泄漏。

编辑：

听起来好像是查询在进行许多连接。在这种情况下，目标是避免这种情况。我们可以利用这样一个事实，即我们正在寻找相同的不同案例wp_usermeta.meta_key 用于构建不需要所有联接的查询的值：

function messages_notify() {
    global $post;
    // if post already published, abort
    if($post->post_status == \'publish\') {
        return;
    }
    // get districts ticked, else abort
    $post_districts = get_the_terms($post->ID, \'message_district\');
    if(empty($post_districts)) return;

    // Build a list of districts to get users from.
    $districts = array(
        \'Northeast\' => \'whprms_district_ne\', 
        \'North Central\' => \'whprms_district_nc\', 
        \'Southeast\' => \'whprms_district_se\', 
        \'Southwest\' => \'whprms_district_sw\', 
        \'West\' => \'whprms_district_w\', 
        //\'Another\' => \'whprms_district_XX\', 
    );

    $searchDistricts = array();
    $districtNames = array_keys($districts);
    foreach($post_districts as $d){
        if(in_array($d->name, $districtNames){
            $searchDistricts[] = $districts[$d->name];
        }
    }

    $districts = implode(\' OR \', array_map(function($s){ return "wp_usermeta.meta_key = \'{$s}\'"; }, $searchDistricts));  // Squash it down into an sql-compatible WHERE subclause.

    $sql = "SELECT DISTINCT wp_users.* 
    FROM wp_users 
    INNER JOIN wp_usermeta ON (wp_users.ID = wp_usermeta.user_id) 
    WHERE 
    -- This part isolates to keys in the list of districts
    ({$districts}) 
    -- Where the value of the district is 1.
    AND CAST(wp_usermeta.meta_value AS CHAR) = \'1\'
    ORDER BY user_login ASC";

    $district_members = $wpdb->WHATEVER_THE_CUSTOM_QUERY_METHOD_IS_CALLED($sql);

    $attachment_args = array(\'post_type\' => \'attachment\', \'orderby\' => \'date\', \'order\' => \'ASC\', \'numberposts\' => -1, \'post_status\' => NULL, \'post_parent\' =>$post->ID);
    $attachments = get_posts($attachment_args);
    if ($attachments) {
        $att_array = array();
        foreach ($attachments as $attachment) {
            $att_array[] = get_the_title($attachment->ID);
        }
    }

    // message only users with desired role(s)
    $bcc = array();
    foreach($district_members as $district_member) {
        // Don\'t use user_can()! It\'s a DB hit!
        //if(user_can($district_member->ID, \'board_members\') || user_can($district_member->ID, \'members\')) {  //@TODO:  Look at $district_member->caps
        if(in_array(\'board_members\', $district_member->roles) || in_array(\'members\', $district_member->roles)) {
            $bcc[] = $district_member->user_email;
        }
    }

    $subject = \'WHPRMS Message: \'.$post->post_title;
    $message = \'New message posted by \';
    if(user_can($post->post_author, \'administrator\')) {
        $message .= get_the_author_meta(\'user_nicename\', $post->post_author)."\\n\\r";
    }
    else {
        $message .= get_the_author_meta(\'first_name\', $post->post_author).\' \'.get_the_author_meta(\'last_name\', $post->post_author)."\\n\\r"; 
    }

    $message .= \'Excerpt: \'.stripslashes(substr($post->post_content, 0, 240)).\'...\'."\\n\\r";
    $message .= \'Link: \'.get_permalink($post->ID)."\\n\\r";

    $message .= \'District(s): \'.implode(\', \', $the_districts)."\\n\\r";
    if (!empty($att_array)) {
        $message .= \'Attachment(s): \'.implode(\', \', $att_array)."\\n\\r";
    }

    $message .= \'You are receiving this message because you belong to one of the districts mentioned above.\';

    $chunked_bcc = array_chunk($bcc, 25);

    foreach($chunked_bcc as $bcc_chunk){
        $headers = array();
        $headers[\'Bcc\'] = \'BCC: \'.implode(\', \', $bcc_chunk);
        wp_mail(\'[email protected]\', $subject, $message, $headers);
    }

}

无论调用什么\\u CUSTOM\\u QUERY\\u METHOD\\u。用任何正确的方法替换此方法get_users() 已提供foreach($district_members as $district_member). 这个user_can() 方法是对每个正在循环的用户进行2次不必要的DB命中。您已经在查询返回的结果中拥有了用户的功能，请改用它