php – UUID cassandra排序？

<?php 
uniqid ("serverA");//generate something like; serverA4b3403665fea6
?>

我可以通过二级索引等选择它们:(生日例子来自phpcassa)

$column_family = new ColumnFamily($conn,'Indexed1');
$index_exp = CassandraUtil::create_index_expression('birthdate',1984);
$index_clause = CassandraUtil::create_index_clause(array($index_exp));
$rows = $column_family->get_indexed_slices($index_clause);
// returns an Iterator over:
//    array('winston smith' => array('birthdate' => 1984))

foreach($rows as $key => $columns) {
    // Do stuff with $key and $columns
    Print_r($columns)
}

但是我只希望查询每页有30个最新添加的用户(创建的密钥)和多页面布局,每个页面显示较旧的密钥

我目前发现的唯一选择是使用来自phpcassa的uuid

uuid1() generates a UUID based on the current time and the MAC
address of the machine.

• Pros: Useful if you want to be able to sort your UUIDs by creation time.
• Cons: Potential privacy leakage since it reveals which computer it was generated on and at what time.
• Collisions possible: If two UUIDs are generated at the exact same time (within 100 ns) on the same machine. (Or a few other unlikely
  marginal cases.)

uuid2() doesn’t seem to be used anymore.

uuid3() generates a UUID by taking an MD5 hash of an arbitrary name
that you choose within some namespace (e.g. URL,domain name,etc).

• Pros: Provides a nice way of assigning blocks of UUIDs to different namespaces. Easy to reproduce the UUID from the name.
• Cons: If you have a unique name already,why do you need a UUID?
• Collisions possible: If you reuse a name within a namespace,or if there is a hash collision.

uuid4() generates a completely random UUID.

• Pros: No privacy concerns. Don’t have to generate unique names.
• Cons: No structure to UUIDs.
• Collisions possible: If you use a bad random number generator,reuse a random seed,or are very,very unlucky.

uuid5() is the same as uuid3(),except using a SHA-1 hash instead
of MD5. Officially preferred over uuid3().

但这意味着我必须重写一些部分获得碰撞的可能性.

我有没有想到的智能黑客？