Memcache::replace
This is just two minor things about memcache that might not be perfectly clear, the limits on key and data sizes and what happen to flags in the memcache protocol.
* There is a max key size of 250 anything bigger gets truncated. There is also a (1MB - 42 bytes) limit on the data.
* In the memcache protocol there is a 16bit, 32bit in newer version, flag that you can set to whatever you want because memcache doesn't do anything with the flags. The php api doesn't let you get the flags because php uses the flags for php's own use such as "MEMCACHE_COMPRESSED" and I decided to test if it was doing something because it wasn't part of the memcache protocol.
<?php
$memcache = new Memcache();
$memcache->connect("127.0.0.1", 11211);
// Since memcache truncates the keys at 250 bytes both the get "250 a's" and "251 a's" will find the key in the cache
echo "*** Truncate key test ***<br>";
echo "set 251: " . ($memcache->set(str_repeat("a", 251), "value", 0, 1) ? "t" : "f") . "<br>";
echo "get 249: " . (($ret = $memcache->get(str_repeat("a", 249))) !== false ? "'$ret'" : "f") . "<br>";
echo "get 250: " . (($ret = $memcache->get(str_repeat("a", 250))) !== false ? "'$ret'" : "f") . "<br>";
echo "get 251: " . (($ret = $memcache->get(str_repeat("a", 251))) !== false ? "'$ret'" : "f") . "<br>";
echo "delete: " . ($memcache->delete(str_repeat("a", 250)) ? "t" : "f") . "<br><br>";
echo "*** Compress value test ***<br>";
echo "set 1024*1024-42: " . ($memcache->set("test", str_repeat("a", 1024*1024-42), 0, 1) ? "t" : "f") . "<br>";
echo "set 1024*1024-41: " . ($memcache->set("test", str_repeat("a", 1024*1024-41), 0, 1) ? "t" : "f") . "<br>";
echo "set 1024*1024 compressed: " . ($memcache->set("test", str_repeat("a", 1024*1024), MEMCACHE_COMPRESSED, 1) ? "t" : "f") . "<br>";
echo "delete: " . ($memcache->delete("test") ? "t" : "f") . "<br>";
$memcache->close();
?>
Output:
*** Truncate key test ***
set 251: t
get 249: f
get 250: 'value'
get 251: 'value'
delete: t
*** Compress value test ***
set 1024*1024-42: t
set 1024*1024-41: f
set 1024*1024 compressed: t
delete: t
Memcache::set
(PECL memcache:0.2-2.1.2)
Memcache::set — Store data at the server
Descrição
Memcache::set() stores an item var with key on the memcached server. Parameter expire is expiration time in seconds. If it's 0, the item never expires (but memcached server doesn't guarantee this item to be stored all the time, it could be deleted from the cache to make place for other items). You can use MEMCACHE_COMPRESSED constant as flag value if you want to use on-the-fly compression (uses zlib).
Also you can use memcache_set() function.Nota: Remember that resource variables (i.e. file and connection descriptors) cannot be stored in the cache, because they cannot be adequately represented in serialized state.
Parâmetros
- 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).
Valor Retornado
Retorna TRUE em caso de sucesso ou FALSE em falhas.
Exemplos
Exemplo #1 Memcache::set() example
<?php
/* procedural API */
/* connect to memcached server */
$memcache_obj = memcache_connect('memcache_host', 11211);
/*
set value of item with key 'var_key'
using 0 as flag value, compression is not used
expire time is 30 seconds
*/
memcache_set($memcache_obj, 'var_key', 'some variable', 0, 30);
echo memcache_get($memcache_obj, 'var_key');
?>
Exemplo #2 Memcache::set() example
<?php
/* OO API */
$memcache_obj = new Memcache;
/* connect to memcached server */
$memcache_obj->connect('memcache_host', 11211);
/*
set value of item with key 'var_key', using on-the-fly compression
expire time is 50 seconds
*/
$memcache_obj->set('var_key', 'some really big variable', MEMCACHE_COMPRESSED, 50);
echo $memcache_obj->get('var_key');
?>
User Contributed Notes
Memcache::set
Memcache::set
Sc00bz
19-Jul-2007 05:20
19-Jul-2007 05:20