分布式事務內存數據庫：MemDB

MemDB 是全球首個支持分布式事務的 MongoDB。

高性能和可伸縮

• 快速的內存數據訪問，高達 25,000 ops (single doc read/write) /碎片 (each shard take one CPU core).

• 系統可水平伸縮

• 沒有單點瓶頸

真正的分布式 ACID 事務

• 在分布式環境真正支持 ACID (Stands for Atomicity, Consistency, Isolation, Durability) 事務

• MemDB 讓 MongoDB 支持 ACID 事務

兼容 MongoDB 和 Mongoose

• 直接使用 MongoDB 的查詢 API

• 內置 Mongoose 支持

高可用性

• 每個碎片都有一個或者多個 slaves，不會發生單點故障

MemDB shell：

架構：

Mdbgoose：

var memdb = require('memdb-client');
var P = memdb.Promise;
var mdbgoose = memdb.goose;
// Define player schema
var playerSchema = new mdbgoose.Schema({
    _id : String,
    name : String,
    areaId : Number,
    deviceType : Number,
    deviceId : String,
    items : [mdbgoose.SchemaTypes.Mixed],
}, {collection : 'player'});
// Define player model
var Player = mdbgoose.model('player', playerSchema);
var main = P.coroutine(function*(){
    // Connect to memdb
    yield mdbgoose.connectAsync({
        shards : { // specify all shards here
            s1 : {host : '127.0.0.1', port: 31017},
            s2 : {host : '127.0.0.1', port: 31018},
        }
    });
    // Make a transaction in s1
    yield mdbgoose.transactionAsync(P.coroutine(function*(){
        var player = new Player({
            _id : 'p1',
            name: 'rain',
            areaId : 1,
            deviceType : 1,
            deviceId : 'id1',
            items : [],
        });
        // insert a player
        yield player.saveAsync();
        // find player by id
        var doc = yield Player.findByIdAsync('p1');
        console.log('%j', doc);
        // find player by areaId, return array of players
        var docs = yield Player.findAsync({areaId : 1});
        console.log('%j', docs);
        // find player by deviceType and deviceId
        player = yield Player.findOneAsync({deviceType : 1, deviceId : 'id1'});
        // update player
        player.areaId = 2;
        yield player.saveAsync();
        // remove the player
        yield player.removeAsync();
    }), 's1');
});
if (require.main === module) {
    main().finally(process.exit);
}

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