Question

我在使用c＃查询MongoDb时遇到了一个问题。问题是我没有返回正确的结果或正确的结果数。我不知道确切的结果数，但它应该小于100;相反，我收到大约350k-500k的结果（其中许多是空的）。另一个问题是该程序需要10分钟才能完成处理。

您可以在以下内容中看到有问题的代码部分：

public List<BsonDocument> find_All_Documents_With_pIDs()
    {            
        List<string> databases = new List<string>();
        List<BsonDocument> pDocs = new List<BsonDocument>(); 
        databases.AddRange(mongo_Server.GetDatabaseNames());

        //iterate through each db in mongo
        foreach (string dbName in databases)
        {
            List<string> collections = new List<string>();
            var database = mongo_Server.GetDatabase(dbName);
            collections.AddRange(database.GetCollectionNames());

            //iterate through each collection
            foreach (string colName in collections)
            {
                var collection = database.GetCollection(colName);

                //Iterate through each document
                foreach (var document in collection.FindAllAs<BsonDocument>())
                {   
                    //Get all documents that have a pID in either the main document or its sub document                     
                    IMongoQuery query = Query.Exists(document.GetElement("_id").ToString().Remove(0,4) + ".pID");
                    IMongoQuery subQuery = Query.Exists(document.GetElement("_id").ToString() + ".SubDocument.pID");
                    pDocs.AddRange(collection.Find(query));
                    pDocs.AddRange(collection.Find(subQuery));
                }
            }
        }

        //Theres a collection used earlier in the program to backup the documents before processing. Not removing the documents from the list found in this location will result in duplicates. 
        return remove_Backup_Documents_From_List(pIDs);
    }

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编辑：

以下是收到的数据的截屏。并非所有数据都如下所示为空，但非常大的数据是：

Answer 1

您的脚本首先从数据库中提取所有文档

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="proj">
  hello
</div>

然后为每个人组装一个查询。这可能是查询速度太慢的原因。

作为替代方案，您可以执行以下操作：

collection.FindAllAs<BsonDocument>()

这样您组合的查询只返回设置了foreach (string colName in collections) { var collection = database.GetCollection(colName); //Query for all documents that have pID IMongoQuery query = Query.And([Query.Exists("pID"), // The field exists Query.NE("pID", BsonNull.Value), //It is not "null" Query.NE("pID", BsonString.Null)]); //It is not empty i.e. = "" //Query for all documents that have Subdocument.pID IMongoQuery subQuery = Query.And([Query.Exists("SubDocument.pID"), // The field exists Query.NE("SubDocument.pID", BsonNull.Value), //It is not "null" Query.NE("SubDocument.pID", BsonString.Null)]); //It is not empty i.e. = "" IMongoQuery totalQuery = Query.Or([query, subQuery]); List<BsonDocument> results = collection.Find(totalQuery); if (results.Count > 0) { pDocs.AddRange(results); //Only add to pDocs if query returned at least one result } }或pID字段的文档。

MongoDB上的C＃查询没有返回正确的结果

1 个答案: