Memcache::addServer
Add a memcached server to connection pool
&reftitle.description;
boolMemcache::addServer
stringhost
intport
boolpersistent
intweight
inttimeout
intretry_interval
boolstatus
callbackfailure_callback
Memcache::addServer adds a server to the connection
pool. The connection, which was opened using Memcache::addServer
will be automatically closed at the end of script execution, you can also close it
manually with Memcache::close.
You can also use the memcache_add_server function.
When using this method (as opposed to Memcache::connect() and
Memcache::pconnect()) the network connection is not established
until actually needed. Thus there is no overhead in adding a large number of servers
to the pool, even though they might not all be used.
Failover may occur at any stage in any of the methods, as long as other
servers are available the request the user won't notice. Any kind of
socket or Memcached server level errors (except out-of-memory) may trigger
the failover. Normal client errors such as adding an existing key will not
trigger a failover.
This function has been added to Memcache version 2.0.0.
&reftitle.parameters;
host
Point to the host where memcached is listening for connections. This parameter
may also specify other transports like unix:///path/to/memcached.sock
to use UNIX domain sockets, in this case port must also
be set to 0.
port
Point to the port where memcached is listening for connections.
This parameter is optional and its default value is 11211. Set this
parameter to 0 when using UNIX domain sockets.
persistent
Controls the use of a persistent connection. Default to &true;.
weight
Number of buckets to create for this server which in turn control its
probability of it being selected. The probability is relative to the
total weight of all servers.
timeout
Value in seconds which will be used for connecting to the daemon. Think
twice before changing the default value of 1 second - you can lose all
the advantages of caching if your connection is too slow.
retry_interval
Controls how often a failed server will be retried, the default value
is 15 seconds. Setting this parameter to -1 disables automatic retry.
Neither this nor the persistent parameter has any
effect when the extension is loaded dynamically via dl.
Each failed connection struct has its own timeout and before it has expired
the struct will be skipped when selecting backends to serve a request. Once
expired the connection will be successfully reconnected or marked as failed
for another retry_interval seconds. The typical
effect is that each web server child will retry the connection about every
retry_interval seconds when serving a page.
status
Controls if the server should be flagged as online. Setting this parameter
to &false; and retry_interval to -1 allows a failed
server to be kept in the pool so as not to affect the key distribution
algoritm. Requests for this server will then failover or fail immediatly
depending on the memcache.allow_failover setting.
Default to &true;, meaning the server should be considered online.
failure_callback
Allows the user to specify a callback function to run upon encountering an
error. The callback is run before failover is attemped. The function takes
two parameters, the hostname and port of the failed server.
&reftitle.returnvalues;
&return.success;
&reftitle.examples;
Memcache::addServer example
addServer('memcache_host', 11211);
$memcache->addServer('memcache_host2', 11211);
/* procedural API */
$memcache_obj = memcache_connect('memcache_host', 11211);
memcache_add_server($memcache_obj, 'memcache_host2', 11211);
?>
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&reftitle.seealso;
Memcache::connect
Memcache::pconnect
Memcache::close
Memcache::setServerParams
Memcache::getServerStatus