http://blog.csdn.net/uixor_/article/details/6758565

  ubuntu10.10 desktop,安装了memcached，后来写了一个php文件来测试memcache：
[php] view plaincopyprint?
01.<?php  
02.$mem = new Memcache;  
03.$mem->connect('127.0.0.1',11211);  
04.$mem->delete('key');  
05.?>  
<?php
$mem = new Memcache;
$mem->connect('127.0.0.1',11211);
$mem->delete('key');
?>

结果在delete的时候老是报错：

[plain] view plaincopyprint?
01.coinsight@insight-ubuntu:~$ php clear.php      
02.PHP Notice:  MemcachePool::delete(): Server 127.0.0.1 (tcp 11211, udp 0)   
03.failed with: CLIENT_ERROR bad command line format.  Usage: delete <key> [noreply]     
04. (0) in /home/coinsight/clear.php on line 4    
05.coinsight@insight-ubuntu:~$  
coinsight@insight-ubuntu:~$ php clear.php    
PHP Notice:  MemcachePool::delete(): Server 127.0.0.1 (tcp 11211, udp 0) 
failed with: CLIENT_ERROR bad command line format.  Usage: delete <key> [noreply]   
 (0) in /home/coinsight/clear.php on line 4  
coinsight@insight-ubuntu:~$

查找了半天原因发现在delete后面加个参数就可以了，而且这个参数必须是0，其它的值同样报错：

[php] view plaincopyprint?
01.<?php  
02.$mem = new Memcache;  
03.$mem->connect('127.0.0.1',11211);  
04.$mem->delete('key',0);  
05.?>