Released ordered KVS Mio 0.0.1alpha

We have released Mio - a distributed Skip Graph based orderd KVS 0.0.1alpha.(mio-0.0.1-alpha.tar.gz)

What is Mio?

In short, Mio is memcached + "range search".

Mio suports range search queries like "get 10 datum which key are between key1 and key2". N.B. At present, it is in alpha quality.

Building and Installing

• Install a recent version of Erlang.

• make

• make install with Environment variables for configuration. TARGET_DIR: Installation target directory. SBIN_DIR: sbin direcotry.

  sudo TARGET_DIR=/user/local/mio SBIN_DIR=/usr/sbin/ make install

Running Mio

# Run first node named mio1 with verbose mode on host FQDN_of_your_host (default port 11211)
% mio -v -n mio1@FQDN_of_your_host

# Run second node named mio2 on host FQDN_of_your_host2.

# With -i option, indidate the introducer node.

% mio -v -n mio2@FQDN_of_your_host2 -i mio1@FQDN_of_your_host

# Run third node named mio3 on host FQDN_of_your_host (port 11411).

% mio -v -n mio3@FQDN_of_your_host -i mio1@FQDN_of_your_host -p 11411

API

You can access to Mio using memcached protocol.

Currently the following commands are supported.

• get
• set
• delete
• quit
• stats
• range_search
  get_multi("mio:range-search", Key1, Key2, Limit, desc/asc)

Access to mio

Use memcached client libraries to access mio.

Perl

# Example: Access to Mio.
use strict;
use warnings;
use Cache::Memcached;
use Data::Dumper;

my $m = Cache::Memcached->new( { servers => ['127.0.0.1:11211']} );

$m->set( "hello" => "world" );

$m->set( "intel" => "cpu" );

$m->set( "japan" => "Tokyo" );

warn $m->get("hello");

warn $m->get("intel");

warn $m->get("japan");

my $href = $m->get_multi("mio:range-search", "he", "j", "10", "asc");

# Should print

# $VAR1 = {

#           'hello' => 'world',

#           'intel' => 'cpu'

#         };

warn Dumper $href;

PHP

$mem = new Memcached;

$mem->addServer('127.0.0.1', 11211);

$mem->set("hello", "world");

$mem->set("intel", "cpu");

$mem->set("japan", "Tokyo");

printf("%s\n", $mem->get("hello"));

printf("%s\n", $mem->get("intel"));

printf("%s\n", $mem->get("japan"));

var_dump($mem->getMulti(array("mio:range-search", "he", "j", "10", "asc")));

?>

Java

import com.danga.MemCached.*;

import java.util.*;


public class JavaMemcachedClient

{

    public static void main(String[] args)

    {

        String[] serverlist = { "127.0.0.1:11211" };

        SockIOPool pool = SockIOPool.getInstance();

        pool.setServers(serverlist);

        pool.initialize();

        MemCachedClient mc = new MemCachedClient();

        mc.set("hello", "world");

        mc.set("intel", "cpu");

        mc.set("japan", "Tokyo");

        System.out.printf("hello => %s intel => %s japan => %s\n", mc.get("hello"), mc.get("intel"), mc.get("japan"));

        String[] keys = { "mio:range-search", "he", "j", "10", "asc" };

        Map ret = mc.getMulti(keys);

        for (Map.Entry e : ret.entrySet()) {

            System.out.println(e.getKey() + " : " + e.getValue());

        }

    }

}

Algorithm

Mio using "Skip Graph" algorithm. See following articles

• Mio - a distributed Skip Graph based orderd KVS


• PDF: Load Balancing and Locality in Range-Queries Data Structures by James Aspnes.

Author

Written by Taro Minowa(Higepon) higepon@labs.cybozu.co.jp

License

New BSD License