Question

我使用mongoDB C＃驱动程序2.1.1来存储和检索mongoDb集合中的文档。到目前为止，这种方法运行良好，直到一个文档正确存储但驱动程序无法读回。

我使用robomongo（一个监视我的集合中的内容的用户界面）并操纵存储的对象得出了这个结论。它包含一组元素（大约4000个子元素），如果我删除了足够的元素，文档最终可以再次检索。

使用的代码行是：

    public Task<T> FirstOrDefaultAsync(Expression<Func<T, bool>> predicate, CancellationToken cancellationToken = default(CancellationToken))
    {
        return MongoQueryable.FirstOrDefaultAsync(_collection, predicate, cancellationToken);
    }

在你提问之前，我首先想到的是我的子元素集中的一个特定元素在序列化/反序列化时遇到了一些问题并且正在创建问题。我通过删除集合中的随机元素进行测试，只是数字似乎是问题的根源。

Json文档的文本文件大小约为11 Mb - 我现在将尝试获得更相关的对象的实际大小。

我可以添加的其他内容是，在mondoDb日志文件中，只有当我尝试选择“超大”文档时才会出现一行：

2016-06-29T19:30:45.982+0200 I COMMAND  [conn12] command MYCOLLECTIONDb.$cmd command: aggregate 
{ aggregate: "XXXX", pipeline: [ { $match: { _id: "5773e0e9a1152d259c7d2e50" } }, { $limit: 1 } ]
, cursor: {} } keyUpdates:0 writeConflicts:0 numYields:0 reslen:4188200 locks:{ Global:
 { acquireCount: { r: 6 } }, MMAPV1Journal: { acquireCount: 
{ r: 3 } }, Database: { acquireCount: { r: 3 } }, Collection: { acquireCount: { R: 3 } } } 109ms

（XXXX是我的自定义对象）

所以我想知道你是否知道造成这个问题的原因，以及我应该试着去看的任何暗示，因为我的想法已经不多了：）

EDIT_1：这基本上就是我对象的结构：

[DataContract]
public class MyClass
{
    [DataMember]
    public string _id { get; set; }

    [DataMember]
    public string XmlPreference { get; set; }

    [DataMember]
    public string XmlMarketDates { get; set; }

    [DataMember]
    public IEnumerable<ClassB> Lines { get; set; }
}

[DataContract]
public class ClassB
{
    [DataMember]
    public string UniqueId { get; set; }

    [DataMember]
    public string ParentId { get; set; }

    [DataMember]
    public Dictionary<string, ClassC> DataMapping {get; set;}
}

和ClassC只是一个7个整数和一个对象属性的容器。还在找东西：）

编辑2：我只使用mongoDb C＃驱动程序2.1.1发布版本重现了该错误。这是代码：

using MongoDB.Bson;
using MongoDB.Driver.Linq;
using MongoDB.Driver;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;

namespace TestingMongoDbCsharpDriver
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Debugging starting...");

            try 
            {
                MongoDB.Driver.MongoClient myClient = new MongoDB.Driver.MongoClient("mongodb://localhost:27010");
                var db = myClient.GetDatabase("DocumentStoreDb");
                var collection = db.GetCollection<DocumentModel>("TestOverload");

                Console.WriteLine("Collection TestOverload found");


                Random rand = new Random(999999999);
                DocumentModel toInsert = null;
                for (int lineNb = 1; lineNb < 50000; lineNb += 1000)
                {
                    string id = rand.Next().ToString();
                    Console.WriteLine(string.Format("\nCreating document with id '{0}' and {1} lines...", id, lineNb));
                    toInsert = Funcs.Create(id, lineNb);
                    Console.WriteLine("Created.");

                    // Saving and waiting for it to finish
                    collection.InsertOneAsync(toInsert).Wait();
                    Console.WriteLine("Inserted.");

                    // retrieving it
                    var filter = new BsonDocument("_id", new BsonDocument("$eq", id));

                    var cursor = collection.FindAsync<DocumentModel>(filter).Result;                    
                    cursor.MoveNextAsync().Wait();
                    string messFilterMethod = cursor.Current.Count() == 1 ? "Retrieved" : "Not retrieved. Bug confirmed";
                    Console.WriteLine("With Filter: " + messFilterMethod);

                    var model = MongoQueryable.FirstOrDefaultAsync(collection.AsQueryable(), e => e._id == id).Result;
                    string mess = model != null ? "Retrieved" : "Not retrieved. Bug confirmed";
                    Console.WriteLine("With AsQueryable: " + mess);

                    // Removing it
                    collection.DeleteOneAsync(filter).Wait();
                    Console.WriteLine("Deleted.\n");

                    Console.ReadKey();
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("\n\nERROR: " + e.Message);
            }
            Console.WriteLine("\n\n**************** NO BUG *************\n");
        }

    }


    public static class Funcs 
    {
        public static DocumentModel Create(string uniqueId, int nbLines)
        {
            Random random = new Random(2000000);
            List<MyDocumentSubElement> listOk = new List<MyDocumentSubElement>();

            for (int lines = 0; lines < nbLines; ++lines)
            {
                Dictionary<string, SnapCellValueStyle> newDico = new Dictionary<string, SnapCellValueStyle>();
                for (int i = 0; i < 10; ++i)
                {
                    int idSnap = random.Next();
                    var snap = new SnapCellValueStyle()
                    {
                        alignment = idSnap,
                        Value = "okkkkkkkkkkzzzzkk"
                    };
                    newDico.Add("newKey_" + idSnap.ToString(), snap);
                }

                MyDocumentSubElement doc = new MyDocumentSubElement()
                {
                    Icon = 516,
                    Name = "name du truc",
                    ParentId = "parent id",
                    type = SubElementType.T3,
                    UniqueId = "uniqueId_" + random.Next().ToString(),
                    MapColumnNameToCellValue = newDico
                };
                listOk.Add(doc);
            }

            int headerId = random.Next();
            MyDocumentHeader temp = new MyDocumentHeader()
            {
                Comment = "comment",
                Date = DateTime.Now,
                ExtractionId = headerId,
                Id = "id ok _ " + headerId,
                Name = "Name really interesting name",
                OwnerId = 95115,
                RootFolioId = 51,
                SnapshotViewId = MyDocumentType.Type2
            };

            DocumentModel toInsert = new DocumentModel()
            {
                _id = uniqueId,
                Header = temp,
                XmlMarketDates = "<xmlPrefok65464f6szf65ze4f6d2f1ergers5fvefref3e4f05e4f064z68f4xd35f8eszf40s6e40f68z4f0e8511xf340ed53f1d51zf68d4z61ef644dcdce4f64zef84zOKok>><>>",
                XmlPreference = "<<zefaiunzhduiaopklzpdpakzdplapdergergfdgergekâzda4684z16ad84s2dd0486za04d68a04z8d0s1d d4az80d46az4d651s1d8 154efze40f6 4ze65f40 65ze40f6z4e>><>>>",
                Lines = listOk
            };

            return toInsert;
        }  
    }

    // Imitation of SnapshotDocModel
    [DataContract]
    public class DocumentModel
    {
        [DataMember]
        public string _id { get; set; }

        [DataMember]
        public MyDocumentHeader Header { get; set; }

        [DataMember]
        public string XmlPreference { get; set; }

        [DataMember]
        public string XmlMarketDates { get; set; }

        [DataMember]
        public IEnumerable<MyDocumentSubElement> Lines { get; set; }
    }

    [DataContract]
    public class MyDocumentHeader
    {
        [DataMember]
        public string Id { get; set; }
        [DataMember]
        public string Name { get; set; }
        [DataMember]
        public int OwnerId { get; set; }
        [DataMember]
        public string Comment { get; set; }
        [DataMember]
        public DateTime Date { get; set; }
        [DataMember]
        public int RootFolioId { get; set; }
        [DataMember]
        public MyDocumentType SnapshotViewId { get; set; }
        [DataMember]
        public int ExtractionId { get; set; }
    }

    [DataContract]
    public class MyDocumentSubElement
    {
        [DataMember]
        public string UniqueId { get; set; }

        [DataMember]
        public string ParentId { get; set; }

        [DataMember]
        public int Icon { get; set; }

        [DataMember]
        public SubElementType type { get; set; }

        [DataMember]
        public Dictionary<string, SnapCellValueStyle> MapColumnNameToCellValue { get; set; }

        [DataMember]
        public string Name { get; set; }
    }

    public class SnapCellValueStyle
    {
        public object Value { get; set; }
        public int alignment { get; set; }
        public int Red { get; set; }
        public int Green { get; set; }
        public int Blue { get; set; }
        public int currency { get; set; }
        public int decimalPoint { get; set; }
        public int kind { get; set; }
        public int style { get; set; }
    }

    #region enum
    public enum MyDocumentType
    {
        Undefined,
        Type1,
        Type2,
        Type3,
        Type4,
        Type5
    }

    public enum SubElementType
    {
        T1,
        T2,
        T3
    }
    #endregion
}

如果你测试它，你会发现AsQueryable方法不再适用的地方，因为文档仍然可以通过使用过滤器的方法检索。

Answer 1

在c＃mongo db驱动程序的2.2.4版本中修复了问题（可能包含错误https://jira.mongodb.org/browse/CSHARP-1645）

谢谢：）

使用C＃Driver 2.1.1在MongoDb集合中存储的对象的最大大小是多少？

1 个答案: