I’ve never thought about deleting a Memcache key is a difficult task. It took me few hours to figure out a working solution. No kidding. FYI, I am using PHP 5.4<\/p>\n
Suppose you store a very expensive data into the Memcache, and you decide to delete it later. According to the PHP documentation, it should be very simple:<\/p>\n
\r\n$memcache_obj->delete('key_to_delete');\r\n\r\nor\r\n\r\nmemcache_delete($memcache_obj, 'key_to_delete');\r\n<\/pre>\n\nHowever, this method only works with scalar variables, such as string, integer, double, float, Boolean etc. It does not work with non-scalar variables such as array, object etc.\n<\/p>\n
\nI have tried many different ways, such as setting the value to something else, e.g.,\n<\/p>\n
\r\n$memcache->set('key_to_delete', 'deleted');\r\n<\/pre>\nor making the key to expire immediately:<\/p>\n
\r\n$memcache->set('key_to_delete', 'deleted', 0, 1);\r\n$memcache->set('key_to_delete', 'deleted', 0, -1);\r\n<\/pre>\nUnfortunately, none of these methods worked in my case (my variable is a non-scalar array). So, I ended up doing it in a low-level way: Bypassing the PECL-Memcache (PHP Library) and talk to the Memcache server directly. Guess what, it works very well. The variable gets deleted!<\/p>\n
\r\nfunction MEMCACHE_DEL_HASH($key){\r\n\t\r\n\tif ($key == '') return FALSE;\r\n\t\r\n\t$socket = @fsockopen('localhost', 11211);\r\n\t$command = \"delete {$key}\";\r\n\t\r\n\tfwrite($socket, $command.\"\\r\\n\");\r\n\tfclose($socket);\r\n\t\r\n\treturn true;\r\n}\r\n<\/pre>\nAnd it is super easy to call this function:<\/p>\n
\r\nMEMCACHE_DEL_HASH('key_to_delete');\r\n<\/pre>\nFeel free to modify this function such that you can pass in the connector, port or do anything you like.<\/p>\n
That’s it! Have fun with Memcache.<\/p>\n
–Derrick<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"