Please note that after flushing, you have to wait a certain amount of time (in my case < 1s) to be able to write to Memcached again. If you don't, Memcached::set() will return 1, although your data is in fact not saved.
(PECL memcache >= 1.0.0)
Memcache::flush — Flush all existing items at the server
Memcache::flush() immediately invalidates all existing items. Memcache::flush() doesn't actually free any resources, it only marks all the items as expired, so occupied memory will be overwritten by new items. Also you can use memcache_flush() function.
Returns TRUE on success or FALSE on failure.
Example #1 Memcache::flush() example
<?php
/* procedural API */
$memcache_obj = memcache_connect('memcache_host', 11211);
memcache_flush($memcache_obj);
/* OO API */
$memcache_obj = new Memcache;
$memcache_obj->connect('memcache_host', 11211);
$memcache_obj->flush();
?>
Please note that after flushing, you have to wait a certain amount of time (in my case < 1s) to be able to write to Memcached again. If you don't, Memcached::set() will return 1, although your data is in fact not saved.
From the memcached mailing list:
"The flush has a one second granularity. The flush will expire all items up to the ones set within the same second."
It is imperative to wait at least one second after flush() command before further actions like repopulating the cache. Ohterwise new items < 1 second after flush() would be invalidatet instantaneous.
Example:
<?php
$memcache->flush();
$time = time()+1; //one second future
while(time() < $time) {
//sleep
}
$memcache->set('key', 'value'); // repopulate the cache
?>