Memcached Client Routines

Collaboration diagram for Memcached Client Routines:

Data Structures
struct	apr_memcache_server_t
struct	apr_memcache_t
struct	apr_memcache_value_t
struct	apr_memcache_stats_t

Typedefs
typedef struct apr_memcache_conn_t	apr_memcache_conn_t
typedef struct apr_memcache_server_t	apr_memcache_server_t
typedef apr_uint32_t(*	apr_memcache_hash_func) (void *baton, const char *data, const apr_size_t data_len)
typedef struct apr_memcache_t	apr_memcache_t
typedef apr_memcache_server_t *(*	apr_memcache_server_func) (void *baton, apr_memcache_t *mc, const apr_uint32_t hash)

Enumerations
enum	apr_memcache_server_status_t { APR_MC_SERVER_LIVE , APR_MC_SERVER_DEAD }

Functions
apr_uint32_t	apr_memcache_hash (apr_memcache_t *mc, const char *data, const apr_size_t data_len)
apr_uint32_t	apr_memcache_hash_crc32 (void *baton, const char *data, const apr_size_t data_len)
apr_uint32_t	apr_memcache_hash_default (void *baton, const char *data, const apr_size_t data_len)
apr_memcache_server_t *	apr_memcache_find_server_hash (apr_memcache_t *mc, const apr_uint32_t hash)
apr_memcache_server_t *	apr_memcache_find_server_hash_default (void *baton, apr_memcache_t *mc, const apr_uint32_t hash)
apr_status_t	apr_memcache_add_server (apr_memcache_t *mc, apr_memcache_server_t *server)
apr_memcache_server_t *	apr_memcache_find_server (apr_memcache_t *mc, const char *host, apr_port_t port)
apr_status_t	apr_memcache_enable_server (apr_memcache_t *mc, apr_memcache_server_t *ms)
apr_status_t	apr_memcache_disable_server (apr_memcache_t *mc, apr_memcache_server_t *ms)
void	apr_memcache_set_retry_period (apr_memcache_t *mc, apr_time_t retry_period)
apr_time_t	apr_memcache_get_retry_period (apr_memcache_t *mc)
apr_status_t	apr_memcache_server_create (apr_pool_t *p, const char *host, apr_port_t port, int min, int smax, int max, apr_interval_time_t ttl, apr_memcache_server_t **ns)
apr_status_t	apr_memcache_create (apr_pool_t *p, apr_uint16_t max_servers, apr_uint32_t flags, apr_memcache_t **mc)
apr_status_t	apr_memcache_getp (apr_memcache_t *mc, apr_pool_t *p, const char *key, char **baton, apr_size_t *len, apr_uint16_t *flags)
void	apr_memcache_add_multget_key (apr_pool_t *data_pool, const char *key, apr_hash_t **values)
apr_status_t	apr_memcache_multgetp (apr_memcache_t *mc, apr_pool_t *temp_pool, apr_pool_t *data_pool, apr_hash_t *values)
apr_status_t	apr_memcache_set (apr_memcache_t *mc, const char *key, char *baton, const apr_size_t data_size, apr_uint32_t timeout, apr_uint16_t flags)
apr_status_t	apr_memcache_add (apr_memcache_t *mc, const char *key, char *baton, const apr_size_t data_size, apr_uint32_t timeout, apr_uint16_t flags)
apr_status_t	apr_memcache_replace (apr_memcache_t *mc, const char *key, char *baton, const apr_size_t data_size, apr_uint32_t timeout, apr_uint16_t flags)
apr_status_t	apr_memcache_delete (apr_memcache_t *mc, const char *key, apr_uint32_t timeout)
apr_status_t	apr_memcache_incr (apr_memcache_t *mc, const char *key, apr_int32_t n, apr_uint32_t *nv)
apr_status_t	apr_memcache_decr (apr_memcache_t *mc, const char *key, apr_int32_t n, apr_uint32_t *new_value)
apr_status_t	apr_memcache_version (apr_memcache_server_t *ms, apr_pool_t *p, char **baton)
apr_status_t	apr_memcache_stats (apr_memcache_server_t *ms, apr_pool_t *p, apr_memcache_stats_t **stats)

Detailed Description

Typedef Documentation

apr_memcache_conn_t

typedef struct apr_memcache_conn_t apr_memcache_conn_t

Opaque memcache client connection object

apr_memcache_hash_func

typedef apr_uint32_t(* apr_memcache_hash_func) (void *baton, const char *data, const apr_size_t data_len)

apr_memcache_server_func

typedef apr_memcache_server_t*(* apr_memcache_server_func) (void *baton, apr_memcache_t *mc, const apr_uint32_t hash)

apr_memcache_server_t

typedef struct apr_memcache_server_t apr_memcache_server_t

Memcache Server Info Object

apr_memcache_t

typedef struct apr_memcache_t apr_memcache_t

Enumeration Type Documentation

apr_memcache_server_status_t

enum apr_memcache_server_status_t

Specifies the status of a memcached server

Enumerator
APR_MC_SERVER_LIVE	Server is alive and responding to requests
APR_MC_SERVER_DEAD	Server is not responding to requests

Function Documentation

apr_memcache_add()

apr_status_t apr_memcache_add	(	apr_memcache_t *	mc,
		const char *	key,
		char *	baton,
		const apr_size_t	data_size,
		apr_uint32_t	timeout,
		apr_uint16_t	flags
	)

Adds value by key on the server

Parameters

mc	client to use
key	null terminated string containing the key
baton	data to store on the server
data_size	length of data at baton
timeout	time for the data to live on the server
flags	any flags set by the client for this key

Returns

APR_SUCCESS if the key was added, APR_EEXIST if the key already exists on the server.

apr_memcache_add_multget_key()

void apr_memcache_add_multget_key	(	apr_pool_t *	data_pool,
		const char *	key,
		apr_hash_t **	values
	)

Add a key to a hash for a multiget query if the hash (*value) is NULL it will be created

Parameters

data_pool	pool from where the hash and their items are created from
key	null terminated string containing the key
values	hash of keys and values that this key will be added to

Returns

apr_memcache_add_server()

apr_status_t apr_memcache_add_server	(	apr_memcache_t *	mc,
		apr_memcache_server_t *	server
	)

Adds a server to a client object

Parameters

mc	The memcache client object to use
server	Server to add

Remarks

Adding servers is not thread safe, and should be done once at startup.

Warning

Changing servers after startup may cause keys to go to different servers.

apr_memcache_create()

apr_status_t apr_memcache_create	(	apr_pool_t *	p,
		apr_uint16_t	max_servers,
		apr_uint32_t	flags,
		apr_memcache_t **	mc
	)

Creates a new memcached client object

Parameters

p	Pool to use
max_servers	maximum number of servers
flags	Not currently used
mc	location of the new memcache client object

apr_memcache_decr()

apr_status_t apr_memcache_decr	(	apr_memcache_t *	mc,
		const char *	key,
		apr_int32_t	n,
		apr_uint32_t *	new_value
	)

Decrements a value

Parameters

mc	client to use
key	null terminated string containing the key
n	number to decrement by
new_value	new value after decrementing

apr_memcache_delete()

apr_status_t apr_memcache_delete	(	apr_memcache_t *	mc,
		const char *	key,
		apr_uint32_t	timeout
	)

Deletes a key from a server

Parameters

mc	client to use
key	null terminated string containing the key
timeout	time for the delete to stop other clients from adding

apr_memcache_disable_server()

apr_status_t apr_memcache_disable_server	(	apr_memcache_t *	mc,
		apr_memcache_server_t *	ms
	)

Disable a Server

Parameters

mc	The memcache client object to use
ms	Server to Disable

apr_memcache_enable_server()

apr_status_t apr_memcache_enable_server	(	apr_memcache_t *	mc,
		apr_memcache_server_t *	ms
	)

Enables a Server for use again

Parameters

mc	The memcache client object to use
ms	Server to Activate

apr_memcache_find_server()

apr_memcache_server_t* apr_memcache_find_server	(	apr_memcache_t *	mc,
		const char *	host,
		apr_port_t	port
	)

Finds a Server object based on a hostname/port pair

Parameters

mc	The memcache client object to use
host	Hostname of the server
port	Port of the server

Returns

Server with matching Hostname and Port, or NULL if none was found.

apr_memcache_find_server_hash()

apr_memcache_server_t* apr_memcache_find_server_hash	(	apr_memcache_t *	mc,
		const apr_uint32_t	hash
	)

Picks a server based on a hash

Parameters

mc	The memcache client object to use
hash	Hashed value of a Key

Returns

server that controls specified hash

See also

apr_memcache_hash

apr_memcache_find_server_hash_default()

apr_memcache_server_t* apr_memcache_find_server_hash_default	(	void *	baton,
		apr_memcache_t *	mc,
		const apr_uint32_t	hash
	)

server selection compatible with the standard Perl Client.

apr_memcache_get_retry_period()

apr_time_t apr_memcache_get_retry_period

(

apr_memcache_t *

mc

)

Get the retry period for retrying a dead server

Parameters

mc	The memcache client object to use

Returns

retry_period Period that must have passed until a server that was declared dead is retried.

apr_memcache_getp()

apr_status_t apr_memcache_getp	(	apr_memcache_t *	mc,
		apr_pool_t *	p,
		const char *	key,
		char **	baton,
		apr_size_t *	len,
		apr_uint16_t *	flags
	)

Gets a value from the server, allocating the value out of p

Parameters

mc	client to use
p	Pool to use
key	null terminated string containing the key
baton	location of the allocated value
len	length of data at baton
flags	any flags set by the client for this key

Returns

apr_memcache_hash()

apr_uint32_t apr_memcache_hash	(	apr_memcache_t *	mc,
		const char *	data,
		const apr_size_t	data_len
	)

Creates a crc32 hash used to split keys between servers

Parameters

mc	The memcache client object to use
data	Data to be hashed
data_len	Length of the data to use

Returns

crc32 hash of data

Remarks

The crc32 hash is not compatible with old memcached clients.

apr_memcache_hash_crc32()

apr_uint32_t apr_memcache_hash_crc32	(	void *	baton,
		const char *	data,
		const apr_size_t	data_len
	)

Pure CRC32 Hash. Used by some clients.

apr_memcache_hash_default()

apr_uint32_t apr_memcache_hash_default	(	void *	baton,
		const char *	data,
		const apr_size_t	data_len
	)

hash compatible with the standard Perl Client.

apr_memcache_incr()

apr_status_t apr_memcache_incr	(	apr_memcache_t *	mc,
		const char *	key,
		apr_int32_t	n,
		apr_uint32_t *	nv
	)

Increments a value

Parameters

mc	client to use
key	null terminated string containing the key
n	number to increment by
nv	new value after incrementing

apr_memcache_multgetp()

apr_status_t apr_memcache_multgetp	(	apr_memcache_t *	mc,
		apr_pool_t *	temp_pool,
		apr_pool_t *	data_pool,
		apr_hash_t *	values
	)

Gets multiple values from the server, allocating the values out of p

Parameters

mc	client to use
temp_pool	Pool used for temporary allocations. May be cleared inside this call.
data_pool	Pool used to allocate data for the returned values.
values	hash of apr_memcache_value_t keyed by strings, contains the result of the multiget call.

Returns

apr_memcache_replace()

apr_status_t apr_memcache_replace	(	apr_memcache_t *	mc,
		const char *	key,
		char *	baton,
		const apr_size_t	data_size,
		apr_uint32_t	timeout,
		apr_uint16_t	flags
	)

Replaces value by key on the server

Parameters

mc	client to use
key	null terminated string containing the key
baton	data to store on the server
data_size	length of data at baton
timeout	time for the data to live on the server
flags	any flags set by the client for this key

Returns

APR_SUCCESS if the key was added, APR_EEXIST if the key did not exist on the server.

apr_memcache_server_create()

apr_status_t apr_memcache_server_create	(	apr_pool_t *	p,
		const char *	host,
		apr_port_t	port,
		int	min,
		int	smax,
		int	max,
		apr_interval_time_t	ttl,
		apr_memcache_server_t **	ns
	)

Creates a new Server Object

Parameters

p	Pool to use
host	hostname of the server
port	port of the server
min	minimum number of client sockets to open
smax	soft maximum number of client connections to open
max	hard maximum number of client connections
ttl	time to live in microseconds of a client connection
ns	location of the new server object

See also

apr_reslist_create

Remarks

min, smax, and max are only used when APR_HAS_THREADS

apr_memcache_set()

apr_status_t apr_memcache_set	(	apr_memcache_t *	mc,
		const char *	key,
		char *	baton,
		const apr_size_t	data_size,
		apr_uint32_t	timeout,
		apr_uint16_t	flags
	)

Sets a value by key on the server

Parameters

mc	client to use
key	null terminated string containing the key
baton	data to store on the server
data_size	length of data at baton
timeout	time in seconds for the data to live on the server
flags	any flags set by the client for this key

apr_memcache_set_retry_period()

void apr_memcache_set_retry_period	(	apr_memcache_t *	mc,
		apr_time_t	retry_period
	)

Set the retry period for retrying a dead server

Parameters

mc	The memcache client object to use
retry_period	Period that must have passed until a server that was declared dead is retried.

apr_memcache_stats()

apr_status_t apr_memcache_stats	(	apr_memcache_server_t *	ms,
		apr_pool_t *	p,
		apr_memcache_stats_t **	stats
	)

Query a server for statistics

Parameters

ms	server to query
p	Pool to allocate answer from
stats	location of the new statistics structure

apr_memcache_version()

apr_status_t apr_memcache_version	(	apr_memcache_server_t *	ms,
		apr_pool_t *	p,
		char **	baton
	)

Query a server's version

Parameters

ms	server to query
p	Pool to allocate answer from
baton	location to store server version string