简而言之,这可以端到端地完成~9 毫秒与文档数据库。我将在下面介绍所需的更改,以及它们为何/如何影响结果。
DocumentDB 中的第一个查询总是需要更长的时间,因为它执行一些设置工作(获取 DocumentDB 分区的物理地址)。接下来的几个请求需要更长的时间来预热连接池。后续查询将与您的网络一样快(由于 SSD 存储,DocumentDB 中的读取延迟非常低)。
例如,如果您修改上面的代码来测量,例如 10 个读数,而不是仅第一个读数,如下所示:
using (DocumentClient client = new DocumentClient(new Uri(EndpointUrl), AuthorizationKey))
{
long totalRequests = 10;
var database = client.CreateDatabaseQuery().Where(db => db.Id == "FamilyRegistry").AsEnumerable().FirstOrDefault();
Stopwatch watch = new Stopwatch();
for (int i = 0; i < totalRequests; i++)
{
watch.Start();
var documentCollection = client.CreateDocumentCollectionQuery("dbs/"+ database.Id)
.Where(c => c.Id == "FamilyCollection").AsEnumerable().FirstOrDefault();
Console.WriteLine("Finished read {0} in {1}ms ", i, watch.ElapsedMilliseconds);
watch.Reset();
}
}
Console.ReadKey();
我从雷德蒙德的桌面上针对 Azure West US 数据中心运行得到以下结果,即大约50毫秒。这些数字可能会有所不同,具体取决于网络连接以及客户端与托管 DocumentDB 的 Azure DC 的距离:
Finished read 0 in 217ms
Finished read 1 in 46ms
Finished read 2 in 51ms
Finished read 3 in 47ms
Finished read 4 in 46ms
Finished read 5 in 93ms
Finished read 6 in 48ms
Finished read 7 in 45ms
Finished read 8 in 45ms
Finished read 9 in 51ms
接下来,我从默认网关切换到 Direct/TCP 连接,以将延迟从两跳改进为一跳,即将初始化代码更改为:
using (DocumentClient client = new DocumentClient(new Uri(EndpointUrl), AuthorizationKey, new ConnectionPolicy { ConnectionMode = ConnectionMode.Direct, ConnectionProtocol = Protocol.Tcp }))
现在通过 ID 查找集合的操作已完成23毫秒:
Finished read 0 in 197ms
Finished read 1 in 117ms
Finished read 2 in 23ms
Finished read 3 in 23ms
Finished read 4 in 25ms
Finished read 5 in 23ms
Finished read 6 in 31ms
Finished read 7 in 23ms
Finished read 8 in 23ms
Finished read 9 in 23ms
当您从也在同一 Azure DC 中运行的 Azure VM 或辅助角色运行相同的结果时会怎样?相同的操作完成大约9毫秒!
Finished read 0 in 140ms
Finished read 1 in 10ms
Finished read 2 in 8ms
Finished read 3 in 9ms
Finished read 4 in 9ms
Finished read 5 in 9ms
Finished read 6 in 9ms
Finished read 7 in 9ms
Finished read 8 in 10ms
Finished read 9 in 8ms
Finished read 9 in 9ms
所以,总结一下:
- 对于性能测量,请允许使用一些测量示例来说明 DocumentDB 客户端的启动/初始化。
- 请使用 TCP/Direct 连接以获得最低延迟。
- 如果可能,请在同一 Azure 区域内运行。
- 如果您遵循这些步骤,您可以获得出色的性能,并且您将能够使用 DocumentDB 获得最佳性能数据。