Mongodb mapreduce为大量文档提供错误收集

Question

我收集了2,000,000份文件。当我运行mapreduce查询时，它会提供一个集合作为180,000个文档的结果。我的map reduce函数的代码如下：

db.products.mapReduce(
    function(){
        var key=this.category_id;
        var value={value:[{
             id:this._id,
             status:this.status,
             additional_images:this.additional_images,
             image:this.image,
             product_url:this.product_url,
             colors:this.colors,
             api:this.api,
             sku:this.sku,
             price:this.price,
             api_updated_on:this.api_updated_on,
             description:this.description,
             brand:this.brand,
             category_name:this.category_name,
             category_id:this.category_id,
             name:this.name,
             product_id:this.product_id,
             count:1
            }]
        };
        emit(key,value);
    },

    function(key,values){
        var objcollection={value:[]};
        var count=1;
            values.forEach( function(item) {
                item=item.value[0];
                //var test_obj={sku:"",name:"",catid:"",productid:"",count:""};
                var item_obj={
                        id:"",
                        status:"",
                        additional_images:"",
                        image:"",
                        product_url:"",
                        colors:"",
                        api:"",
                        sku:"",
                        product_hash:"",
                        price:"",
                        api_updated_on:"",

                        description:"",
                        brand:"",
                        category_name:"",
                        category_id:"",
                        category_id:"",
                        name:"",
                        product_id:"",
                        count:""
                };

                item_obj.id=item.id;
                item_obj.status=item.status;
                item_obj.additional_images=item.additional_images;
                item_obj.image=item.image;
                item_obj.product_url=item.product_url;
                item_obj.colors=item.colors;
                item_obj.api=item.api;
                item_obj.sku=item.sku;
                item_obj.price=item.price;
                item_obj.api_updated_on=item.api_updated_on;
                item_obj.description=item.description;
                item_obj.brand=item.brand;
                item_obj.category_name=item.category_name;
                item_obj.category_id=item.category_id;
                item_obj.name=item.name;
                item_obj.product_id=item.product_id;
                item_obj.count=count;

                objcollection.value.push(item_obj);
                count++;
            });
        return objcollection;

    },
    {
        out:'productmapreduce'
    }
);

当我监视终端上的mongod时，会显示一条消息

命令：mapReduce {$ msg：＆＃34;查询不记录（太大）＆＃34; } keyUpdates：0 numYields：264 keys（micros）W：3097 r：7111563 w：769188 reslen：140 5749ms