c# – MongoDB 2.4.8上限集合和tailable游标消耗所有内存

我们目前正在探索MongoDB中的Capped Collections和Tailable Cursors来创建一个通知排队系统.但是,在创建一个简单的 LinqPad测试(下面的代码)后,我们注意到在运行时,Mongo不断分配内存,直到没有更多可用资源,即使我们没有插入任何记录.这种分配一直​​持续到使用所有系统RAM为止,此时Mongo只是停止响应.

由于我们是Capped Collections和Tailable Cursors的新手,我想确保在提交错误之前我们没有错过任何明显的东西.

注意：我们尝试使用以下代码打开和关闭日记,但结果相同.

>平台：Windows Server 2012 64位
> MongoDB：版本2.4.8 64位
>司机：官方C#10gen v1.8.3.9

Linqpad脚本

var conn = new MongoClient("mongodb://the.server.url").GetServer().GetDatabase("TestDB");

if(!conn.CollectionExists("Queue")) {

    conn.CreateCollection("Queue",Collectionoptions
        .SetCapped(true)
        .SetMaxSize(100000)
        .SetMaxDocuments(100)
    );

    //Insert an empty document as without this 'cursor.IsDead' is always true
    var coll = conn.GetCollection("Queue");
    coll.Insert(
        new BsonDocument(new Dictionary<string,object> {
            { "PROCESSED",true },}),WriteConcern.UnackNowledged
    );
}

var coll = conn.GetCollection("Queue");
var query = coll.Find(Query.EQ("PROCESSED",false))
    .SetFlags(QueryFlags.AwaitData | QueryFlags.NoCursorTimeout | QueryFlags.TailableCursor);

var cursor = new MongoCursorEnumerator<BsonDocument>(query);

while(true) {
    if(cursor.MoveNext()) {
        string.Format(
            "{0:yyyy-MM-dd HH:mm:ss} - {1}",cursor.Current["Date"].ToUniversalTime(),cursor.Current["X"].Asstring
        ).Dump();

        coll.Update(
            Query.EQ("_id",cursor.Current["_id"]),Update.Set("PROCESSED",true),WriteConcern.UnackNowledged
        );
    } else if(cursor.IsDead) {
        "DONE".Dump();
        break;
    }
}

Query.EQ("PROCESSED",false)

var conn = new MongoClient("mongodb://the.server.url").GetServer().GetDatabase("TestDB");

if(conn.CollectionExists("Queue")) {
    conn.DropCollection("Queue");
}

conn.CreateCollection("Queue",Collectionoptions
    .SetCapped(true)
    .SetMaxSize(100000)
    .SetMaxDocuments(100)
    .SetAutoIndexId(true)
);

//Insert an empty document as without this 'cursor.IsDead' is always true
var coll = conn.GetCollection("Queue");
coll.Insert(
    new BsonDocument(new Dictionary<string,object> {
        { "PROCESSED",{ "Date",DateTime.UtcNow },{ "X","test" }
    }),WriteConcern.UnackNowledged
);

//Create query based on latest document id
BsonValue lastId = BsonMinKey.Value;
var query = coll.Find(Query.GT("_id",lastId))
    .SetFlags(QueryFlags.AwaitData | QueryFlags.NoCursorTimeout | QueryFlags.TailableCursor);

var cursor = new MongoCursorEnumerator<BsonDocument>(query);

while(true) {
    if(cursor.MoveNext()) {
        string.Format(
            "{0:yyyy-MM-dd HH:mm:ss} - {1}",cursor.Current["X"].Asstring
        ).Dump();
    } else if(cursor.IsDead) {
        "DONE".Dump();
        break;
    }
}