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Memcache Client

6.0-SNAPSHOT 5.5 5.4 5.3 5.2 5.1 5.0

A Memcache client written in any language can talk directly to a Hazelcast cluster. No additional configuration is required.

Hazelcast Memcache Client only supports ASCII protocol. Binary Protocol is not supported.

To be able to use a Memcache client, you must enable the Memcache client request listener service using either one of the following configuration options:

1 - Using the network configuration element:

  • XML

  • YAML

<hazelcast>
    ...
    <network>
        <memcache-protocol enabled="true"/>
    </network>
    ...
</hazelcast>
hazelcast:
  network:
    memcache-protocol:
      enabled: true

2 - Using the advanced-network configuration element:

  • XML

  • YAML

<hazelcast>
    ...
    <advanced-network>
        <memcache-server-socket-endpoint-config name="memcache">
            <port auto-increment="false" port-count="10">6000</port>
        </memcache-server-socket-endpoint-config>
    </advanced-network>
    ...
</hazelcast>
hazelcast:
  advanced-network:
    memcache-server-socket-endpoint-config:
      name: memcache
      port:
        auto-increment: false
        port-count: 10
        port: 6000

Memcache Client Code Examples

Assume that your cluster members are as shown below.

Members [5] {
  Member [10.20.17.1:5701]
  Member [10.20.17.2:5701]
  Member [10.20.17.4:5701]
  Member [10.20.17.3:5701]
  Member [10.20.17.5:5701]
}

Assume that you have a PHP application that uses PHP Memcache client to cache things in Hazelcast. All you need to do is have your PHP Memcache client connect to one of these members. It does not matter which member the client connects to because the Hazelcast cluster looks like one giant machine (Single System Image). Here is a PHP client code example.

<?php
    $memcache = new Memcache;
    $memcache->connect( '10.20.17.1', 5701 ) or die ( "Could not connect" );
    $memcache->set( 'key1', 'value1', 0, 3600 );
    $get_result = $memcache->get( 'key1' ); // retrieve your data
    var_dump( $get_result ); // show it
?>

Notice that Memcache client connects to 10.20.17.1 and uses port 5701. Here is a Java client code example with SpyMemcached client:

MemcachedClient client = new MemcachedClient(
    AddrUtil.getAddresses( "10.20.17.1:5701 10.20.17.2:5701" ) );
client.set( "key1", 3600, "value1" );
System.out.println( client.get( "key1" ) );

If you want your data to be stored in different maps, for example to utilize per map configuration, you can do that with a map name prefix as in the following example code.

MemcachedClient client = new MemcachedClient(
    AddrUtil.getAddresses( "10.20.17.1:5701 10.20.17.2:5701" ) );
client.set( "map1:key1", 3600, "value1" ); // store to *hz_memcache_map1
client.set( "map2:key1", 3600, "value1" ); // store to hz_memcache_map2
System.out.println( client.get( "key1" ) ); // get from hz_memcache_map1
System.out.println( client.get( "key2" ) ); // get from hz_memcache_map2

hz_memcache prefix\_ separates Memcache maps from Hazelcast maps. If no map name is given, it is stored in a default map named hz_memcache_default.

An entry written with a Memcache client can be read by another Memcache client written in another language.

Unsupported Operations for Memcache

  • CAS operations are not supported. In operations that get CAS parameters, such as append, CAS values are ignored.

  • Only a subset of statistics are supported. Below is the list of supported statistic values.

    • cmd_set

    • cmd_get

    • incr_hits

    • incr_misses

    • decr_hits

    • decr_misses

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