mapreduce - RavenDB 中多映射索引与空间索引失败

Question

我想搜索属于用户(在我附近)的东西。我定义了以下索引，但没有获得合并的结果集:

public class Things_ByLocation : AbstractMultiMapIndexCreationTask<Things_ByLocation.ThingsByLocationResult>
{
    public class ThingsByLocationResult
    {
        public string ThingId { get; set; }
        public string UserId { get; set; }
        public double Latitude { get; set; }
        public double Longitude { get; set; }
    }

    public Things_ByLocation()
    {
        AddMap<Thing>(things => from t in things
                                select new
                                {
                                    ThingId = t.Id,
                                    UserId = (string)null,
                                    Latitude = 0,
                                    Longitude = 0,
                                    _ = (object)null,
                                });
        AddMap<User>(users => from u in users
                                select new
                                {
                                    ThingId = (string)null,
                                    UserId = u.Id,
                                    Latitude = u.Latitude,
                                    Longitude = u.Longitude,
                                    _ = SpatialIndex.Generate(u.Latitude, u.Longitude)
                                });

        Reduce = results => from result in results
                            group result by result.ThingId into g
                            let userId = g.Select(x => x.UserId).Where(t => !string.IsNullOrWhiteSpace(t)).FirstOrDefault()
                            let lat = g.Select(x => x.Latitude).Where(t => t != 0).FirstOrDefault()
                            let lng = g.Select(x => x.Longitude).Where(t => t != 0).FirstOrDefault()
                            select new
                            {
                                ThingId = g.Key,
                                UserId = userId,
                                Latitude = lat,
                                Longitude = lng,
                                _ = SpatialIndex.Generate(lat, lng)
                            };

        Store(x => x.ThingId, FieldStorage.Yes);
        Store(x => x.UserId, FieldStorage.Yes);
    }
}

结果如下所示:

{
  "ThingId": "Thing/Id26",
  "UserId": null,
  "Longitude": "0",
  "__spatialShape": "0.000000 0.000000"
}

我的模型:

public class User
{
    public string Id { get; set; }
    public double Latitude { get; set; }
    public double Longitude { get; set; }
}

public class Thing
{
    public string Id { get; set; }
    public double Name { get; set; }
    public double Description { get; set; }
    public string UserId { get; set; }
}

关于我做错了什么有什么想法吗？如果我将组切换到用户，则用户部分将被填充并且 ThingId 为空。因此，合并过程似乎失败了。我只是不确定为什么。

这也很奇怪，为什么结果显示经度，而不显示纬度属性。

在 RAM 中使用 RavenDB Build 960。

我意识到我可以将位置非规范化到事物中，但这意味着如果用户位置发生变化，我将不得不更新可能的数百个事物。这是首选的 NoSql 方式吗？

更新

根据 Ayende 的建议，我现在有以下内容:

public class Things_ByLocation : AbstractMultiMapIndexCreationTask<Things_ByLocation.ThingsByLocationResult>
{
    public class ThingsByLocationResult
    {
        public string ThingId { get; set; }
        public string UserId { get; set; }
        public double Latitude { get; set; }
        public double Longitude { get; set; }
    }

    public Things_ByLocation()
    {
        AddMap<Thing>(things => from t in things
                                select new
                                {
                                    ThingId = t.Id,
                                    UserId = (string)null,
                                    Latitude = 0,
                                    Longitude = 0
                                });
        AddMap<User>(users => from u in users
                                select new
                                {
                                    ThingId = (string)null,
                                    UserId = u.Id,
                                    Latitude = u.Latitude,
                                    Longitude = u.Longitude
                                });

        Reduce = results => from result in results
                            group result by result.ThingId into g
                            select new
                            {
                                ThingId = g.Key,
                                UserId = g.Select(x => x.UserId).Where(x => x != null).FirstOrDefault(),
                                Latitude = g.Select(x => x.Latitude).Where(t => t != 0).FirstOrDefault(),
                                Longitude = g.Select(x => x.Longitude).Where(t => t != 0).FirstOrDefault()
                            };

        Store(x => x.ThingId, FieldStorage.Yes);
        Store(x => x.UserId, FieldStorage.Yes);
    }
}

索引本身:

Map:
docs.Things
    .Select(t => new {ThingId = t.__document_id, UserId = (String)null, Latitude = 0, Longitude = 0})

Map:
docs.Users
    .Select(u => new {ThingId = (String)null, UserId = u.__document_id, Latitude = ((double)u.Latitude), Longitude = ((double)u.Longitude)})

Reduce:
results
    .GroupBy(result => result.ThingId)
    .Select(g => new {ThingId = g.Key, UserId = g
    .Select(x => x.UserId)
    .Where(x => x != null).FirstOrDefault(), Latitude = g
    .Select(x => ((double)x.Latitude))
    .Where(t => t != 0).FirstOrDefault(), Longitude = g
    .Select(x => ((double)x.Longitude))
    .Where(t => t != 0).FirstOrDefault()})

生成的投影如下所示:

{
  "ThingId": "Thing/Id26",
  "UserId": null,
  "Latitude": null,
  "Longitude": null
}

我似乎在学术上做了一些错误的事情。

Answer 1

尝试:

• 从 map 中删除 SpatialIndex.Generate，它应该只在reduce 上。
• 从reduce中删除SpatialIndex.Generate，然后看看为什么没有按应有的方式获取纬度和经度。