(PECL memcache >= 0.2.0)
Memcache::replace -- memcache_replace — Replace value of the existing item
$memcache
,$key
,$var
,$flag
= ?,$expire
= ?
Memcache::replace() should be used to replace value of
existing item with key
. In case if item with such
key doesn't exists, Memcache::replace() returns
false
. For the rest Memcache::replace() behaves
similarly to Memcache::set() .
key
The key that will be associated with the item.
var
The variable to store. Strings and integers are stored as is, other types are stored serialized.
flag
Use MEMCACHE_COMPRESSED
to store the item
compressed (uses zlib).
expire
Expiration time of the item. If it's equal to zero, the item will never expire. You can also use Unix timestamp or a number of seconds starting from current time, but in the latter case the number of seconds may not exceed 2592000 (30 days).
Example #1 Memcache::replace() example
<?php
$memcache_obj = memcache_connect('memcache_host', 11211);
/* procedural API */
memcache_replace($memcache_obj, "test_key", "some variable", false, 30);
/* OO API */
$memcache_obj->replace("test_key", "some variable", false, 30);
?>
This page mentions that replace should be used rather than set, but gives no reason. Best information I could find was a comment by 'argyleblanket' on the set page. (http://www.php.net/manual/en/memcache.set.php#84032)
"Using set more than once for the same key seems to have unexpected results - it does not behave as a "replace," but instead seems to "set" more than one value for the same key. "get" may return any of the values.
This was tested on a multiple-server setup - behaviour may be different if you only have one server. "