在 MongoDB 5.0、c# 驅動程序中過濾基於時間的數據：得到錯誤（零）結果

Question

我有一個用 MongoDB5.0 引入的 TimeSeries 集合，里面裝滿了大約 100000 個文檔，並希望過濾器工作，例如獲取集合內特定時間范圍的文檔計數。

// Timestamp must be a BSON date (as the doc's say), which is BSONDateTime in c#
// so the time range boundaries for the filter is based on the BSon Default 1/1/1970
// from, to are TimeSpan objects

var dt1 = new DateTime(1970,1,1,0,0,0, DateTimeKind.Utc) + from;
var dt2= new DateTime(1970,1,1,0,0,0, DateTimeKind.Utc) + to;

var filter = Builders<MongoTimeSeriesDocument>.Filter.Gte(x => x.Timestamp, dt1);
filter &= Builders<MongoTimeSeriesDocument>.Filter.Lte(x => x.Timestamp, dt2);

// result: zero
var docCount = await collection.CountDocumentsAsync(filter)
                .ConfigureAwait(false);
// result: zero
var docCount2 = await collection.Find(filter)
                .CountDocumentsAsync()
                .ConfigureAwait(false);

我還注冊了一個 DateTimeSeriealizer：

BsonSerializer.RegisterSerializer(typeof(DateTime), new DateTimeSerializer(DateTimeKind.Utc));

序列化程序不起作用。

這有效：

// result: 70000
var docCount = await collection.CountDocumentsAsync(x => x.Timestamp < new DateTime(2021,11,7,0,0,0, DateTimeKind.Utc))
                .ConfigureAwait(false);

雖然這不起作用（它應該算全部，因為時間戳 > 1970）：

// result: 0
var docCount2 = await collection.CountDocumentsAsync(x => x.Timestamp > new DateTime(1970,1,1,0,0,0, DateTimeKind.Utc))
                .ConfigureAwait(false);
// same with BsonDateTime: result: 0
var docCount2 = await collection.CountDocumentsAsync(x => x.Timestamp > new BsonDateTime(new DateTime(1970,1,1,0,0,0, DateTimeKind.Utc)))
                .ConfigureAwait(false);

Answer 1

在 C# 中，我采用 Bson 方式並傳遞一個$match字符串，該字符串有 2 個表示$gte和$lte表達式。 這適用於 TimeSeries：

var filterStage = new StringBuilder();
            filterStage.Append("{$match:{$and:[ {$expr: {$gte:");
            filterStage.Append("[ \"$Timestamp\",");
            filterStage.Append($"ISODate('{isoFrom}'),");
            filterStage.Append("]}}, {$expr:{ $lte:");
            filterStage.Append("[ \"$Timestamp\",");
            filterStage.Append($"ISODate('{isoTo}')");
            filterStage.Append("]}} ]}}");

            var aggregation = await collection.Aggregate()
                .AppendStage<MongoTimeSeriesDocument>(filterStage.ToString())
                .ToListAsync()
                .ConfigureAwait(false);